To enable the remediation of thisclass of contaminants by persulfate (S2O82–)-based ISCO, we employed a two-phase process to dehalogenateand oxidize a representative halogenated compound .In the first phase, a relatively high concentration of ethanol (1.8M) was added, along with concentrations of S2O82– that are typically used for ISCO . Hexachloroethane underwent rapid dehalogenation when carbon-centeredradicals produced by the reaction of ethanol and radicals formed duringS2O82– decomposition reactedwith carbon–halogen bonds. Unlike conventional ISCO treatment,hexachloroethane transformation and S2O82– decomposition took place on the time scale of dayswithout external heating or base addition. The presence of O2, Cl–, and NO3– delayedthe onset of hexachloroethane transformation when low concentrationsof S2O82– (10 mM) were used,but these solutes had negligible effects when S2O82– was present at concentrations typical of insitu remediation (450 mM). The second phase of the reaction was initiatedafter most of the ethanol had been depleted when thermolytic S2O82– decomposition resulted inproduction of SO4•– that oxidizedthe partially dehalogenated transformation products. With proper precautions,S2O82–-based ISCO with ethanolcould be a useful remediation technology for sites contaminated withfully halogenated compounds.Fully halogenated compounds are difficult to remediateby in situchemical oxidation (ISCO) because carbon–halogen bonds reactvery slowly with the species that typically initiate contaminant transformation:sulfate radical (SO Anew approach is described for in situ remediation of unreactivecontaminants by adding ethanol to facilitate reductive dehalogenation. This limitation arises from the lack ofreactivity of saturated compounds that contain multiple carbon–halogenbonds, such as carbon tetrachloride and hexachloroethane, with SO4•– and •OH. Asa result, their remediation through traditional ISCO methods is challenging.6In situ chemical oxidation (ISCO), thepractice of introducingrelatively high concentrations of oxidants into groundwater and soil,has proven to be an effective means of rapidly remediating sites thatare contaminated with a variety of organic contaminants.2O82– is to be used toremediate sites that contain fully halogenatedcompounds or compounds with multiple difficult-to-oxidize functionalgroups . One possible approach involves the useof carbon-centered radicals produced when an oxidizing radical abstractsan electron from a low molecular weight organic compound. For example,Peyton et al.7 reported the reduction ofcarbon tetrachloride and dinitrotoluene when the UV/H2O2 and UV/ozone processes were employed in the presence of ethanol,respectively. More recently, Zhu et al.8 demonstrated the ability of ethanol radicals, produced by heat activationof S2O82– under oxygen-freesolutions, to dehalogenate carbon tetrachloride.Another approach is neededif S2O82– decomposes in the presenceof low molecular weight organics. O2, Cl–, and HCO3– also can decrease the efficiencyof the process by competing for carbon-centered radicals, SO4•–, •OH, or one of theintermediates produced during the decomposition of S2O82– .10 Chain reactions canalso accelerate the S2O82– decomposition rates. For example, the rate of decomposition of S2O82– ([S2O82–]0 = 40 mM) in the presence of 0.05M was 9 × 10–5 min–1. Itincreased by a factor of approximately 1.1 (1 × 10–4 min–1) and 2.2 (2 × 10–4 min–1) in the presence of 0.2 and 0.4 M ethanol,respectively.11 For ethanol, the productsof transformation reactions initiated by SO4•– or •OH  also can participatein radical reactions, altering the concentrations of radicals involvedin dehalogenation or S2O82– decomposition reactions. Finally, except for fully halogenated compoundsthat are essentially unreactive with SO4•– and •OH, organic contaminants are likely to undergodehalogenation and oxidation reactions simultaneously when S2O82– decomposes in the presence of ethanol,further complicating efforts to understand the reaction mechanisms.Despite itsability to reduce organic contaminants, the potentialfor employing carbon-centered radicals for remediation is uncertaindue to the large number of competing reactions that take place whenS4•– or •OH, we evaluatedthe use of S2O82– and ethanolto transform hexachloroethane, a fully halogenated compound that wouldbe impractical to treat by conventional ISCO. To understand conditionslikely to be encountered during ISCO treatment, the reactions werestudied under acidic conditions  typical of thoseencountered when high concentrations of S2O82– are employed.12 Bymonitoring concentrations of hexachloroethane, S2O82–, O2, and transformation productsunder various conditions, we were able to assess reaction mechanismsand the impact of solutes that could interfere with the transformationprocess. By adding an excess of S2O82– relative to the amount of ethanol initially added to the system,we were able to create a second phase of the process in which partiallydehalogenated reaction products were further transformed and partiallymineralized by SO4•– or •OH.To provide insight into the potential for using carbon-centeredradicals to remediate groundwater that has been contaminated withhalogenated compounds that are difficult to oxidize with SOText S1.Unless otherwise specified, chemicalswere obtained at the highestavailable purity and used without further purification. A list ofchemicals and their sources is summarized in 2S2O8 were prepared in deionized water froma Milli-Q ultrapurewater system (18.2 MΩ·cm at 25 °C). One set was degassedat room temperature by bubbling with N2 to remove O2. To adjust the desired [O2]0, a deoxygenatedNaS2O8 solution was mixed with air-saturatedor deoxygenated deionized water and ethanol. The other set was allowedto equilibrate with the atmosphere for at least 30 min prior to useand mixed with the ethanol solution.Two sets of stock solutions of 500 mM Na2S2O8 stock solution . The initial pH of the solution was around1.5 due to the partial decomposition of S2O82– in the stock solution when 10 mM persulfatesolution was prepared.To study conditions typicalof those employed for remediation,a solution of target compound or ethanol was added to the Na2O82– . Underthese conditions, a small volume of Na2S2O8 stock solution was added to the target compound dissolvedin an ethanolic solution . Without an added buffer, theinitial pH of this solution was around 4.3 under this condition.Experiments were also conducted at amuch lower initial concentrationof SFigure S1). At predetermined times, samples from the water bath were transferredto an ice bath to stop the reaction. After 2 min of cooling, 1 mLaliquots were transferred to 2 mL GC vials containing 1 mL of n-hexane and capped. Liquid–liquid extraction wasconducted in the vial on a shaker for 30 min at room temperature priorto the analysis of an aliquot of the hexane layer by a gas chromatographymass spectrometer (GC/MS).After mixing, solutions were transferred to 9 mL amber glass vialswithout headspace and sealed with a Teflon cap. Capped vials wereheated in a water bath at temperatures ranging from 30 to 50 °C.To conduct experiments at 2 °C, vials were placed in a refrigerator.Samples placed in warm water baths reached the target temperaturewithin 5 min; samples placed in the refrigerator required about 3.5h to reach the target temperature . The method detection limit (MDL) for hexachloroethane was18 nM. MDLs for pentachloroethane, tetrachloroethene, and trichloroethenewere 13, 9, and 21 nM, respectively. A modified version of the U.S.EPA 8270D GC/MS analysis method–), sulfate (SO42–), and chlorate (ClO3–) concentrationswere determined by a modified version of U.S. EPA 300.1 method14 with ion chromatography , an Ion Pac column , and a guard column . The columntemperature was set to 30 °C, and AS23 eluent (4.5 mM NaHCO3 and 0.8 mM Na2CO3) was used. The eluentflow rate was 1.0 mL min–1, and the current was25 mA. A typical anion calibration curve is shown in Figure S4. Under the highly acidic conditions used in theseexperiments, nearly all of the carbonate species are converted intocarbonic acid species  and gaseous carbon dioxide. Including carbonate in the solutionsresulted in the presence of gas bubbles that complicate the analysisof volatile products. Carbonic acid is relatively unreactive withSO4•– and •OH,especially in the presence of high concentrations of ethanol and otherorganic solutes. Therefore, we excluded carbonate from these experiments.Chloride  with a reverse-phase column . Formicacid  and methanol (60:40 v/v %) were used as the eluentwith a 0.4 mL min2O82– was quantified usinga modified version of a previously described method (Text S3).16 A representative S2O82– calibration curve is shown in Figure S6. Dissolved oxygen ([O2])and pH were measured with an Orion STAR A213 meter coupled with theOrion dissolved oxygen probe and a DB-10 pH meter . To ensure accurate O2 analysis, the probewas polished with a polishing disk (Product number: 080513) wheneverneeded due to corrosion by the high concentration of S2O82–. Temperature was measured withan alcohol thermometer .S2O82–  and ethanol (1.8M) along with solutes typically encountered in groundwater , a decrease in the concentrationof S2O82– coincided with transformationof hexachloroethane. At 50 °C, hexachloroethane concentrationsdecreased by over 99.96%  in about 10 min as [S2O82–] decreased by about 66%. Similar results were observedat 30 °C, with slightly slower rates of transformation. At 2°C, complete transformation of hexachloroethane required 3 daysand consumed a little less than half of the S2O82–. In the presence of a lower concentration ofS2O82– , no measurablehexachloroethane or S2O82– transformation was observed over these time intervals  andless than 1.7 mM of the S2O82– were transformed over 3 days in control experiments conducted at2 °C  in the presenceof much lower concentrations of ethanol  with aninitial S2O82– concentrationof 450 mM.In solutions thatinitially contained relatively high concentrations of Sntervals 1c,d. Les2O82– in the presenceof ethanol, only 9.4% and 12.8% of the hexachloroethane was transformedwhen ethanol was replaced by either tert-butanolor methanol, respectively .The faster rate of hexachloroethane transformation in the presenceof ethanol was accompanied by greater S2O82– loss; after 30 min, more than 60% of S2O82– decomposition was observed in thepresence of ethanol, whereas 2.7% and 4.8% of S2O82– had disappeared in the presence of tert-butanol and methanol, respectively . These findings are consistent with results from a previous study11 in which faster S2O82– decomposition rates in the presence of high concentrationsof ethanol were explained by differences in the abilities of alcoholsand certain alcohol transformation products, typically aldehydes,to terminate radical chain reactions.Under conditions that resulted in complete lossof hexachloroethaneby S2O82– in the presenceof 1.8 M ethanol (2O82– thermolysisranged from 3 days at 50 °C to 14 years at 2 °C).17 The faster-than-expected decay of S2O82– may be attributable to radicalchain reactions initiated by the reaction of SO4•– and ethanol 3CHO), produced in 113) tendsto be less reactive with organic compounds and S2O82– than the ethanol radical as indicatedby the slower rate of hexachloroethane transformation  and S2O82– decomposition observed when ethanol was replacedby acetaldehyde .The rate of disappearanceof S ethanol 1b was su ethanol 1 in pure22 or pentachloroethanecarbanion protonation .Thetransformation of hexachloroethane is likely due to hydrogenabstraction 6 and 721tonation 8 and 9:2stested 2 and S1124 or dechlorination of pentachloroethylcarbanion via an internal two electron transfer (24S11).The pentachloroethyl radical and pentachloroethanecarbanion alsocan produce tetrachloroethene by a reaction with ethanol radical (nditions 2 and S11S10). Changes in the relative concentrationsof transformation products with temperature may have been caused bydifferences in the activation energies of the various reactions responsiblefor the formation of each of the measured products as well as subsequentreactions that lowered the concentrations of measured transformationproducts.The relative concentrationsof pentachloroethane and tetrachloroetheneformed during the transformation of hexachloroethane varied with temperature,with relative concentrations of tetrachloroethene increasing withtemperature 2 and S102O82–]0 . Underthese conditions, pentachloroethane and tetrachloroethene accountedfor less than 40% of the carbon loss at the end of the experiment, while measured [Cl–] was 50–100% higher than values predicted ifpentachloroethane and tetrachloroethene were the only transformationproducts .To investigate the mass balance and chloride recoveryduring hexachloroethanetransformation, experiments were conducted at a lower  = 10 mM), each solute inhibitedthe transformation of hexachloroethane  and the conversion of S2O82– . The rateconstants for the reactions of ·CH(CH3)OH with NO3– and NO2– areunknown. In addition to the data in Figure S14, these oxidized nitrogen species are also known to react with thestrong reductant, solvated electron (3)OH, it appears thatthese solutes did not depress the steady-state concentration of theradical enough to slow the rate of contaminant transformation at [S2O82–] = 450 mM. Nevertheless,our initial findings suggest that, under conditions typical of mostcontaminated sites, solutes present in groundwater are unlikely toappreciably slow transformation. This is because the injection fluidis typically prepared using water sources such as tap water or relativelyclean groundwater, which tend to have relatively low concentrationsof chloride, nitrogen species, and other solutes that might interferewith the process.To assess the effectof these solutes on hexachloroethane reductionrates, we repeated several of the previously described experimentswith environmentally realistic concentrations of each of the solutesand high and low concentrations of  ranging from 1 to 50mM, but complete removal of the compound still occurred within 10min of initiating the experiment.Recognizing that injection fluids could becomecontaminated bysolutes such as Cl•OH and SO4•–,37 on the reductiveprocess, an experiment was conducted with low concentrationsof S2O82– in the presenceand absence of the SO4•– scavenger,benzoic acid , the benzoic acid should have competed withethanol for SO4•–. As a result,the rate of transformation of hexachloroethane decreased by about50%, relative to the rate observed in the absence of benzoic acid. The rate of loss of S2O82– also slowed in the presenceof benzoic acid, presumably due to less initiation of chain decompositionreactions . Although the presenceof a cocontaminant that reacts with SO4•– slowed the rate of hexachloroethane reduction at low [S2O82–]0 , itdid not have a measurable effect at higher [S2O82–]0; complete loss of hexachlorobenzenewas observed when 450 mM S2O82– was added . Also, underthe same condition, there was no significant difference in S2O82– decomposition rates in the presence(6.7 × 10–2 min–1) and absence(7.2 × 10–2 min–1) of benzoicacid . We also do not expectinhibition from natural organic matter because it is usually presentat relatively low concentrations compared to organic cocontaminants.38To investigate the effectof organic cocontaminants, sinks for oic acid 20:See reFigure S11 and Text S4). These compounds should be susceptible tooxidation by SO4•–.The second phase of this process (oxidation) may be necessary afterthe fully halogenated compound is lost to transform the dehalogenatedtransformation products , oxidizable contaminant  removal should mainly takeplace through reactions with SO4•–; the fraction of SO4•– thatproduces reducing radicals will drop, and [SO4•–]ss will increase. To gain insight into the shift fromreducing to oxidizing conditions, we conducted experiments with excessS2O82– relative to ethanol,using benzoic acid as a probe for SO4•– , coinciding with the rise in O2 levels due to the oxidation of water by SO4•– through a radical chain reaction ,41 which ispresent at lower concentrations, is less reactive with these transformationproducts  when it is comparedto oxidative SO4•– (Eο = 2.5–3.1 V vs NHE).18 To simulate the transformation of partially dehalogenatedproducts during the second phase of the process, experiments wereconducted in the presence of persulfate at low concentrations of ethanol. Under these conditions, complete mineralization ofthe unsaturated chlorinated compounds was observed with nearly quantitativerecovery of Cl– , which is consistent with previous research on tetrachloroetheneoxidation.42During the second phase, partially dehalogenatedcompounds  are likely to be oxidized,because reductive ethanol radical that reduce the efficacy of radical reactions under less extreme conditions.The reactions of carbon-centered radicals result in the formationof partially dehalogenated products that are less amenable to furtherreduction. If a sufficiently high concentration of S2O82– is initially added, the process can entera second phase in which SO4•– producedby S2O82– activation oxidizespartially dehalogenated compounds and other organic cocontaminants. The second phase of thereaction will require a means of accelerating the rate of S2O82– activation .The sequentialreductive and oxidative treatment process describedhere has the potential to extend the benefits of in situ chemicalremediation with S2O8).In addition to the expense and need for precautions in materials handling, decomposition of S2O82– will subject soils and aquifer sediments to extremeconditions . Ethanol and its oxidation products are less of aconcern because they are oxidized during the second phase of the process.Any residual organics that are not mineralized will likely be degradedby microbes in the soil or groundwater. Nonetheless, exposure to theseextreme conditions could lead to metal mobilization, alter soil structure,and impact microbial communities. In addition to research to assessthe role of iron and other transition metals that might be releasedfrom aquifer solids on the kinetics of reductive processes responsiblefor contaminant removal, research involving authentic aquifer solidsis needed to assess the impacts of this treatment on the physical,chemical, and biological conditions of the subsurface.The fluids injected into the subsurfacecontain relatively highconcentrations of alcohol and oxidant (i.e., 80–200 g/L NaS


We previously found good catalytic properties of Co2FeGe for selective hydrogenation of alkynes and developed nanoparticles of Co2FeGe supported on SiO2. However, the average diameter of the nanoparticles was 23 nm, which is not small enough compared to those of state‐of‐the‐art nanoparticle catalysts. In this study, we developed SiO2‐supported Co2FeGe nanoparticles of <10 nm in diameter. A catalytic test for selective hydrogenation of propyne indicated a partial formation of sites with low selectivity including excess Co atoms. For ammonia decomposition, enhancement of turnover frequency was achieved by reducing the particle size.Heusler alloys  and turnover frequency  for NH3 decomposition (red) were monotonically increased by reducing particle size from 23 nm to 7.5 nm, while those and C3H6 selectivity (cross) for C3H4 hydrogenation (green) did not follow the same monotonic trend.Co Its average particle size was estimated to be 23 nm, however, which could be downsized even more to less than 10 nm as other intermetallic catalysts. was introduced at a flow rate of 30 mL min−1. From room temperature to 250 °C, the products were analyzed by gas chromatography (Agilent 490 Micro GC with PoraPLOT Q column) after waiting 30 min at each temperature. NH3 decomposition was also performed. After heating under H2 gas flow at 800 °C for 1 h, the reactor was flushed by He gas (50 mL min−1) for 10 min at 300 °C to remove hydrogen species adsorbed on a catalyst surface. The reaction was conducted using a gaseous mixture of [1 % NH3/99 % He] at a flow rate of 30 mL min−1 from 300 °C to 600 °C. The products were analyzed by gas chromatography : Porapak N in Sulfinert® tube for NH3 and Molecular Sieve 5 A for N2 and H2) using He carrier gas. A TOF in s−1 was calculated to be a reaction rate in mol s−1 g(Co)−1 divided by the number of CO molecules in mol g(Co)−1 in the pulse adsorption.Catalytic properties were evaluated in a standard flow reactor. The Cθ=8.6° and 9.9°, respectively, are not visible, detection of which was made more difficult due to peak broadening by nanosizing. Although a peak possibly of CoGe was detected at the side of the 220 Co2FeGe peak for sample 1) as reported previously,2FeGe was likely obtained in all samples. The Heusler phase was maintained even when the amount of metals loaded was decreased to reduce the particle size. The crystallite size was estimated from the 220 peak width using the Scherrer equation and is listed in Table Figure −3),2FeGe particles was roughly estimated on the assumption of spherical particles. The amount of CO molecules adsorbed in the pulse adsorption was divided by the surface area as listed in Table −2 are similar for all samples; thus, the estimated particle sizes of samples 2) and 3) in Table Assuming that the average size ratio of crystallites and particles is 15 : 23 also in other samples, the particle size was estimated to be 9.4 nm and 7.5 nm for samples 2) and 3), respectively. Particles around these sizes were actually observed in TEM images as shown in Figure 3H4 hydrogenation. In general, the alkene selectivity tends to be high when the alkyne conversion is less than 100 % because the alkene products desorbed from catalyst surfaces hardly adsorb again due to alkyne molecules adsorbing strongly on the surfaces.[3H4 conversion reached 100 %, sample 1) kept a high C3H6 selectivity over 70 %; however, samples 2 and 3) lost the selectivity, which indicated the existence of low‐selective sites on the catalyst surfaces.Figure surfaces.20, 213H6 selectivity of which was very low compared to the sample 1) with Co : Fe : Ge=1.8 : 1 : 1. This signal that seems to be originated from monometallic Co sites was clearer for the samples 2) and 3) than the sample 1). A peak at 230–240 °C observed for the micron powder was attenuated for samples 2) and 3), which also made the profiles similar to that for the pure Co. Thus, catalytically active sites consisting of excess Co atoms likely formed due to inhomogeneous mixing in synthesis processes or structural disordering. However, the TOF of C3H4 was not so different among the samples 1–3) as listed in Table 3H4 molecules were hydrogenated to C3H6 mainly on the intended active sites without excess Co atoms and the C3H6 molecules were further hydrogenated to C3H8 on a small amount of the excess Co active sites.Figure 3 decomposition. Samples 2) and 3) showed a higher conversion than sample 3). The conversions by samples 2) and 3) were almost the same even though sample 3) contains half as much metal as sample 2).Figure 3 decomposition has been reported as TOF by Ru catalysts depends on the particle size, in which several nanometers give the maximum TOF.5 site, includes low‐coordinated Ru atoms.Thus, TOF monotonically increased with a reduction in the particle size as shown in Table 3 decomposition; however, the C3H6 selectivity was decreased for the C3H4 hydrogenation due to the undesirable active sites likely formed by inhomogeneous mixing in synthesis or structural disordering. The ordered structure is destabilized by nanosizing due to an increase in the number ratio of surface atoms to bulk atoms.0‐type CoPt disorders to A1 (fcc) phase at 825 °C in bulk state, while its particles with a diameter of several nanometers disorders at 500–650 °C.2FeGe does not disorder below the melting point (1128 °C).[2FeGe nanoparticles of <10 nm in diameter with negligible disordering and segregation.By reducing the particle size, TOF was increased for the NH1128 °C).25, 262‐supported Co2FeGe Heusler alloy nanoparticles with different particle sizes were synthesized by changing the amount of metals loaded in the impregnation process. The XRD analysis, the TEM observation, and the CO pulse adsorption indicated that the average particle size was reduced from 23 nm to 7.5 nm. For the C3H4 hydrogenation, the TOF was not so different among the three samples, while the C3H6 selectivity was low in the samples with the particle size of <10 nm. The CO‐TPD indicated that the low selectivity was due to the active sites including excess Co atoms. For the NH3 decomposition, the TOF monotonically increased with the reduction in particle size. This increase was considered due to the increase in low‐coordinated atoms according to the literature.[2FeGe nanoparticles with <10 nm in diameter and revealed that the partial formation of excess Co sites must be excluded in the synthesis processes if the target is a selective reaction.SiOterature.19, 22The authors declare no conflict of interest.1As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re‐organized for online delivery, but are not copy‐edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors.Supporting InformationClick here for additional data file.


Conventionally, the recommended duration of adjuvant chemotherapy of colon cancer had been 6 months. The IDEA Collaboration suggested that shortening capecitabin and oxaliplatin (CAPOX) adjuvant chemotherapy may be possible. S‐1 and oxaliplatin (SOX) treatment is standard treatment in metastatic colorectal cancer in Japan. The aim of this study was to optimize treatment dosage and duration of adjuvant SOX in stage III colon cancer.2 (3 months) or 100 mg/m2 (6 months) of oxaliplatin. The primary endpoint was 3‐year disease‐free survival (DFS) and the null hypothesis for the primary endpoint was that the 3‐year DFS was ≤72% in each arm and was tested with a one‐sided significance level of 10%.This trial was as open‐label multi‐center randomized phase II study. Patients with stage III colon cancer were randomly assigned to 3 months or 6 months of adjuvant SOX treatment in different doses: 130 mg/mp = 0.282) in the 6 months arm and 76.9%  in the 3 months arm. Treatment completion rate and relative dose intensity (RDI) were higher in 3 months than 6 months arm. The adverse events (AE) were similar in both arms.Eighty‐two patients were assigned to the 6 months arm and 81 to the 3 months arm. The 3‐year DFS was 75.0%  adjuvant chemotherapy of 130 mg/m2 (3 months) or 100 mg/m2 (6 months) of oxaliplatin was feasible and safe for the patients with stage III colon cancer. The IDEA Collaboration showed that 0.4% difference in 5‐year overall survival between 3‐month and 6‐month of adjuvant treatment with oxaliplatin‐based regimen for the patients with Stage III colon cancer. It did not show the non‐inferiority of 3‐months.S‐1 contains gimeracil, which helps to inhibit the degradation of 5‐FU in the body, and oteracil, which helps to reduce gastrointestinal side effects normally caused by 5‐FU. It is an oral agent that is converted to 5‐FU in the body as well as capecitabin. The S‐1 and oxaliplatin (SOX) regimen was originally investigated in Japan for colon cancer and advanced gastric cancer. And the SOX and SOX plus bevacizumab regimens are recommended in 1st‐line chemotherapy for the patients with metastatic colorectal cancer in Japanese Society for Cancer of the Colon and Rectum guidelines 2022 for the treatment of colorectal cancer,2 and at 3 months at 130 mg/m2.The aim of our study is basically an exploratory examination of optimal therapeutic dosage and duration of SOX adjuvant treatment. Therefore, we set oxaliplatin dosage at 6 months at 100 mg/m22.1This trial was as open‐label multi‐center randomized phase II study as YCOG1403 study. This study was conducted in the Yokohama Clinical Oncology Group (YCOG) institutes. The institutional review board at Yokohama City University and each study center approved the protocol in accordance with the principles expressed in the Declaration of Helsinki. All patients provided written informed consent prior to enrollment. This study is registered with the UMIN Clinical Trial Registry (UMIN000013825).2.2Patients who had undergone curative resection for stage III colon cancer and enrolled by study investigators were randomized 1:1–6 months and 3 months of adjuvant SOX delivered every 3 weeks in different doses according to stratification factor: primary tumor site (colon or rectosigmoid vs. upper rectum), the number of metastatic lymph nodes (≤3 vs. >3), and institutions.3, neutrophil count ≥1500/mm3, platelet count ≥100 000/mm3, hemoglobin ≥9.0 g/dL, total bilirubin ≤2.0 mg/dL, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤100 IU/L, creatinine clearance  ≥60 mL/min. The exclusion criteria were that the patients had another sever comorbidity, prior chemotherapy or radiation therapy history, history of another cancer in the last 5 years, and the peripheral neuropathy of grade 1 and higher.The inclusion criteria were that an Eastern Cooperative Oncology Group (ECOG) performance status was 0–1, the age was between 20 and 80 years old, and the vital organ function was adequate: white blood cell count ≥3000/mm2.32 (3 months arm) or 100 mg/m2 (6 months arm) of oxaliplatin on day 1 and oral S‐1 80 mg/m2 according to BSA twice a day from the evening of day 1 to the morning of day 15 repeated every 3 weeks. Four cycles and eight cycles SOX was administered to patients in the 3‐month and 6‐month arms, respectively.The treatment was not blinded to patients and investigators. Treatment in SOX included a 2‐hour intravenous infusion of 130 mg/m2.4We assessed the chemotherapy‐induced peripheral neuropathy (CIPN) using the Peri‐neuropathy Questionnaire (PNQ)2.5Patients were evaluated for recurrence with CEA and CA19‐9 value in plasma every 3 months, and chest, abdominal and pelvis computed tomography every 6 months, and colonoscopy every 1 year.2.6The primary endpoint was 3‐year DFS. The secondary endpoints were OS, RDI, treatment completion rate, and AE. Evaluation of AE was based on the CTCAE ver. 4.0.2.7α = 0.1 (one‐sided) for 78 patients in one arm, and the power of the test for the null hypothesis of 72% was 77%. Considering some ineligible cases, the planned sample size was set at 80 cases per arm. The purpose of the primary analysis of this study was to determine whether the 3‐year DFS of protocol treatment in each arm had efficacy that allowed rejection of the threshold (P0) for each arm.ACTS‐CC, JCOG0205, and JFMC33‐0502 studies conducted in Japan verified 5‐FU‐based adjuvant chemotherapy without oxaliplatin and reported a 3‐year DFS of 72.5%–79.3%.Efficacy analysis was performed in all registered and randomized patients. Safety analysis was performed in all patients who had received SOX adjuvant chemotherapy. The DFS and OS were estimated with the Kaplan–Meier method and the Greenwood formula. The one‐sample test for 3‐year DFS was performed using the Greenwood formula to estimate the standard deviation of the complementary log–log transformed survival. The Fisher test and t‐test were employed to compare the treatment completion rates and the mean RDI between arms, respectively. All statistical analyses were performed using the SAS software, version 9.4 or later (SAS Institute) or, the R software, version 4.1.0 or later .33.1Patients were enrolled from nine institutions in Japan that belonged to YCOG and randomly assigned to 6 months or 3 months SOX adjuvant chemotherapy between May 1, 2014, and November 11, 2017. Eighty‐two patients were assigned to the 6 months arm and 81 patients assigned to the 3 months arm. Two cases assigned to the 3 months arm and six cases in 6 months arm were excluded from the primary analyses: four patients in 6 months arm and one patent in 3 months arm could not start protocol treatment because they did not meet starting criteria after randomization, and the mistake in the pathological result were found in one patient in 3 months arm and one patient in 3 months arm after randomization, and the randomization error was found in one case. Finally, the primary analysis was performed in 76 patients in the 6 months and 79 patients in 3 months arm  in 6 months arm and 20 patients (25.3%) in 3 months arm were pathological T4 and 15 patients (19.7%) and 18 patients (22.8%) were pN2, respectively, and there was no difference in the rate of high‐risk stage III patients between two arms (Table 3.2p = 0.282) in the 6 months arm and 76.9%  in the 3 months arm . The 3‐year DFS was 75.0% . The mean RDI of oxaliplatin and S‐1 were 76.9% and 77.4% in the 6 months arm and 82.6% and 85.0% in the 3 months arm, respectively . (Table Treatment completion rate was 73.7% in the 6 months arm and 86.1% in the 3 months arm (3.4p = 0.326). The overall and grade 3 or 4 neutrophil count decrease was 61.8% and 19.7% in 6 months arm, and 41.8% and 13.9% in 3 months arm, respectively. Overall neutropenia was greater in 6 months arms than in 3 months arms  in 6 months arm and there were no patients in 3 months arm Table .4This study was the first study to optimize treatment dosage and duration of SOX regimen in patients with stage III colon cancer in adjuvant setting. The adjuvant treatment of stage III colon cancer after curative surgery is standard with oxaliplatin‐based regimen, FOLFOX or CAPOX, were superior to 5‐FU (MOSAIC) NO16968 Randomized Controlled Phase III Trial.The SOX regimen was shown to be non‐inferior to CAPOX in terms of PFS as a first‐line treatment for metastatic colorectal cancer in a phase III trial conducted in Korea.p < 0.0001)).In adjuvant treatment for the colon cancer, S‐1 was confirmed to be noninferior in DFS compared with UFT / LV in ACTS‐CC trial. It showed that 3‐year DFS was 72.5% in UFT / LV arm and 75.5% in S‐1 arm (HR = 0.85 (95% CI: 0.70–1.03 SOX treatment is one of the standard chemotherapies for the patients with advanced gastric cancer as well as CAPOX treatment. SOX treatment was non‐inferior to S‐1 plus CDDP (SP) treatment in the first‐line chemotherapy for the patients with advanced gastric cancer.The adjuvant SOX treatment has not yet been established for colon cancer. SOX treatment was compared with UFT/ LV in adjuvant setting in ACTS‐CC 02 trial,There was difference in duration and dosage of oxaliplatin between 6 months and 3 months arms. However, the aim of our study is basically an exploratory examination of optimal therapeutic dosage and duration in each arm, although it was not a comparative study between the two arms.2 was because it was the same dose as the ACTS‐CC 02 trial, which was the adjuvant treatment of colon cancer, and the G‐SOX regimen for the treatment of advanced gastric cancer.2 was because it was the same dose as first‐line regimen for metastatic colorectal cancer,2. We showed that 130 mg/m2 dose of oxaliplatin was acceptable and feasible for 3 months in short‐term outcomes.The reason why the oxaliplatin dosage in 6 months arm was 100 mg /m2 in both 3 and 6 months groups of the ACHIEVE trial, and also in 3 months arm of our study. It was 100 mg/m2 in 6 months arm of our study. The treatment completion rates were 86% in 3 months and 60% in 6 months arm in the ACHIEVE trial compared to 86.1% and 73.7% in our study.The duration of adjuvant treatment is as follows. In our study, the 3‐year DFS in 3 months arm was 76.9% compared to 75.0% in the 6 months arm, although our study wasn't a comparative trial between 6 months and 3 months arm. Moreover, this study has failed to show that primary endpoint of 3‐year DFS was superior to 72% for 3 months or 6 months SOX adjuvant therapy. The ACHIEVE trial showed the 3‐year DFS for 3 months and 6 months in CAPOX arm; a 3‐year DFS rate of 81.4%  for 3 months versus 79.7%  for 6 months treatment .One of the merits of the shortening of the duration of adjuvant therapy is reducing the peripheral neuropathy for the patients. In ACHIEVE study, the 3 months oxaliplatin‐based adjuvant therapy resulted in reduction peripheral neuropathy by 1/2 or 1/3 compared to 6 months therapy.4.1Our study had some limitations that should be considered. First, all participant patients of our study were Japanese. And S‐1 is launched in 13 Asian countries  and 17 European countries . It has not been released in USA and some European countries. And it is only approved for gastric cancer in some of them.Secondary, JCOG0910 study was at the prespecified second interim analysis after final accrual, the Data and Safety Monitoring Committee recommended early publication on September 24 because S‐1 could not show non‐inferiority compared with capecitabine for DFS, 2014. Our study was planned in January 2014 and had already started at that time.Thirdly, the outcome of ACTS‐CC 02 was published in 2020. This outcome showed SOX adjuvant regimen wasn't superior to UFT/LV for the high‐risk stage III colon cancer. However, the final randomized cases were on November 17, 2017, in our study.Finally, we tried to collect PNQ from participants after the protocol treatment. However, the PNQ collection rate was low and insufficient to accurately assess the extent of peripheral neuropathy.5The 80% confidence interval of 3‐year DFS was not superior to 72% in both 3 months and 6 months arms for the patients of stage III colon cancer, and primary endpoint was not achieved. However, the SOX regimens were safe in both arms in short outcomes. In conclusion, the SOX regimen was not feasible in long‐term outcomes.This works was funded by TAIHO PHARMACEUTICAL CO. Ltd., Japan under the research contract.Annals of Gastroenterological Surgery.The authors declare no conflicts of interest for this article. The authors, Jun Watanabe and Itaru Endo, are editorial members of Approval of the research protocol: The protocol for this research project has been approved by a suitably constituted Ethics Committee of the Yokohama City University  and it conforms to the provisions of the Declaration of Helsinki.Informed consent: All written informed consent was obtained from the subjects.Registry and the Registration No. of the study: UMIN000013825.Animal Studies: N/A.


The transition is presumably governed by significant suppression of atomic displacement parameters correlated to the evolution of amplitude of atomic modulation functions.Crystals of a coupled molecule of 4-biphenylcarboxy-( l)-phenylalaninate is unusual owing to its monoclinic symmetry within a pseudo-orthorhombic crystal system. The distortion is described by a disparate rotational property around the chiral centers  of the two molecules in the asymmetric unit. Each of these molecules comprises planar biphenyl moieties (φbiphenyl = 0°). Using temperature-dependent single-crystal X-ray diffraction experiments we show that the compound undergoes a phase transition below T ∼ 124 K that is characterized by a commensurate modulation wavevector, q = δ(101), δ = ½. The (3+1)-dimensional modulated structure at T = 100 K suggests that the phase transition drives the biphenyl moieties towards noncoplanar conformations with significant variation of internal torsion angle (φmaxbiphenyl ≤ 20°). These intramolecular rotations lead to dimerization of the molecular stacks that are described predominantly by distortions in intermolecular tilts (θmax ≤ 20°) and small variations in intermolecular distances (Δdmax ≃ 0.05 Å) between biphenyl molecules. Atypical of modulated structures and superstructures of biphenyl and other polyphenyls, the rotations of individual molecules are asymmetric (Δφbiphenyl ≈ 5°) while φbiphenyl of one independent molecule is two to four times larger than the other. Crystal-chemical analysis and phase relations in superspace suggest multiple competing factors involving intramolecular steric factors, intermolecular H—C⋯C—H contacts and weak C—H⋯O hydrogen bonds that govern the distinctively unequal torsional properties of the molecules.Amongst the derivatives of 4-biphenylcarboxylic acid and amino acid esters, the crystal structure of 4-biphenylcarboxy-( Low-temperature phase II is found to be a 2a × b × 2c superstructure of the high-temperature (phase I) structure.In the present study, the temperature-dependent phase transition of 4-biphenylcarboxy-D-superspace approach as a commensurately modulated structure . The origin and stability of phase II is discussed in terms of intramolecular steric factors and intermolecular HC⋯CH contacts and intermolecular hydrogen bonds. It is suggested that the order parameter of the phase transition is correlated with the suppression of dynamic disorder.Structural properties of phase I and the modulated structure have been tabulated and compiled within 2.2.1.et al. . The transition temperature is significantly higher than that of molecular biphenyl . On the other hand, related polyphenyls p-terphenyl and p-quarterphenyl undergo phase transition towards superstructure phases at much higher critical temperatures  is 3:1. This indicates pronounced modulation which is characteristic of modulated molecular crystals 0 with σ1 = σ3 = ½  was redetermined at 160 K using A and B [Fig. 1a)]. Anisotropic atomic displacement parameters (ADPs) of all non-hydrogen atoms were refined. Hydrogen atoms were added to carbon and nitrogen atoms using a riding model in ideal chemical geometry with constraints for isotropic ADPs .Atoms were renamed with suffixes a and b for the two independent molecules et al., 2016Table S2). Finally, positions of the H atoms of NH groups and the parameter corresponding to isotropic extinction correction were refined that further improved supporting information).Owing to the pseudoorthorhombic crystal system, the integrated data was tested for twinning employing twofold rotation along the [100] direction as twin law. This twin law is a true symmetry element in the case of a hypothetical orthorhombic crystal system with point group symmetry 222  and ψ in Fig. 1a)]. In addition, we also observe that the coplanar biphenyl rings are significantly rotated with respect to the amide groups [at T = 200 K: φ2 = 32.8° and 31.2° ] which also remains invariant as a function of temperature.The crystal structure reproduced the values for intramolecular rotations reported those for the structure at Jana2006 and Jana2020. Fractional coordinates of all atoms from the crystal structure at T = 160 K were used in the starting model while retaining the same riding model geometry for hydrogen atoms as in phase I and the average structure was refined as main reflections. In successive steps, an incommensurate (IC) model described by one harmonic wave for displacive modulation describing the atomic modulation functions (AMFs) and basic parameters for anisotropic ADPs for non-hydrogen atoms was refined against main and satellite reflections that resulted in good fit to the diffraction pattern (The modulated structure of phase II at 100 K was refined using q (σ1 and σ3) are rational, three commensurately modulated structures were pursued by fixing the initial phase of the modulation to values t0 = 0, t0 values describe monoclinic space group B21 symmetry for the equivalent 3D 2a × b × 2c superstructure, the third corresponds to triclinic B1 symmetry. The commensurately modulated structure (C) model corresponding to t0 = Since the components of supporting information). However, the C model at t0 = NC = 649 with NIC = 811, further tests in supporting information).As the atomic modulation functions (AMFs) have sinusoidal character, the residual values are similar to the IC model . The refined twin volume in phase II reproduced the value similar to that in phase I . Presumably, the crystal possesses pseudo-merohedral growth twins.The final C model was further improved by refining the parameter corresponding to isotropic extinction correction and AMFs and positions of hydrogen atoms of NH groups  are physically relevant. These sections represent the atomic coordinates in the equivalent twofold superstructure in 3D .In the final commensurately modulated structure model with  Figs. 3 and S5 aa and c axes describes the additional B-centering of the superstructure in phase II.Crystal structures of phase I and phase II have group–subgroup relations and the doubling of the Jana2006 comprises four molecules in the asymmetric unit (Z′ = 4); two each corresponding to molecules A and B of phase I .The covalent bond distances are similar for the independent set of molecules and are practically unaffected by modulation et al., 2021et al., 2019et al., 2016et al., 2015et al., 2003In the present study, discussion is based on the modulated structure in order to establish unique relations between phase I and phase II (Rekis 3 > 0°) within the biphenyl moieties [Fig. 3a)]. The twists about the central C—C bond are significantly different for the two molecules where the torsional modulation of A are 2–4 times larger than those of B  along the three basis vectors where the maximum amplitude are along b for the carbon atoms of biphenyl . Notably, the rotations in the present structure are significantly larger than those reported for molecular biphenyl [φ ≃  ±  5.5° -phenyl systems described by the property that in the later cases two disordered conformations of the molecules freeze by superstructure formation and breaking the monoclinic symmetry of their high-temperature phase.The nature of structural changes in the present system and molecular biphenyl below the phase transition temperature is different to ubiphenyl > uphenylalaninate (Table S4). Compared to 1 are lesser and those in ψ are very small and virtually equal for both A and B [c) and 3d)].A distinctive property of the present modulated structure is the unequal modulation for the two different moieties where A possible reason for the weaker modulations of the atoms around the chiral centers is the directional strong intermolecular N—H⋯O bonds makes large intramolecular rotations unfavorable.2 of molecule A [compare b)] are predominantly described by strong modulations of the molecule’s biphenyl moiety. The asymmetry in rotations of individual molecules (Δ|φ3| ≈ 5°) is determined by the disparate bonding environments of the biphenyl moieties where the inner rings are that are covalently bonded to amide groups while the outer interact weakly via C—H⋯H—C interactions with the phenyl rings of phenylalaninate groups  and 3b)].Note that the observed changes in the rotations of φps Fig. 4. Subsequ1 is greater for molecule A than that of B [compare c)]. The origin of disparate distortions in intramolecular rotations is explained in §3.2It is also observed that the variation in φAA)n and (BB)n stacks which are parallel (θ = 0°) in phase I are tilted with respect to each other [Fig. 3e)]. These tilts (θAA/BB) are of the order of the internal twists (φ3) of the independent biphenyl moieties  The orientation between the biphenyl moieties within the (ABAB)n stacks also vary with ΔθAA/BB ≃ 12° where the value is intermediate to e) with Fig. 3a)]. In addition, intermolecular distances between the biphenyl moieties within the stacks at the two t-sections are different and vary up to ΔdAA/BB ≃ 0.05 Å and ΔdABAB ≃ 0.02 Å [Fig. 3f)].In the modulated structure, the biphenyl moieties in  in t = ; dBB =  in Fig. 3f)]. It could therefore be argued that the dimerization of biphenyl molecular stacks below Tc is predominantly governed by distortion described by molecular rotations rather than intermolecular distances. On the other hand, variation of intermolecular distances between aromatic rings of l-phenylalaninate are similar to those of the biphenyls albeit the interstack rotations of the former are significantly smaller .Overall distortions in 3.2.ortho-hydrogen atoms are displaced away in the plane of the rings to minimize steric hindrance . The difference in twist angles has remarkable effects on the molecular conformation with respect to the distance between the O3 atoms of the amide groups and hydrogen atoms of the chiral centers C3 carbon atoms  and meta  positions are strongly displaced . Subsequently, the ADPs are significantly reduced as compared with phase I . Notably, the decrease of the ADPs (Ueq) from T = 160 K to T = 100 K is larger for those of molecule A than those for B in conjunction with the fact that overall the ADPs are smaller or similar for the former as opposed to phase I, while the square of the amplitude of modulations (u2) are greater for A than those for B [compare Figs. 5b) with 5a)].As noted in §2.2l-phenylalaninate moieties of A are greater than B from T = 160 K to T = 100 K [Fig. 5c)]. Unlike the biphenyl moieties, such apparent switch-over of the ADPs is not observed where the overall values of A are greater than those of B in both phases I and II, while the squares of the AMFs in II are larger for A than those for B . It is possible that the superstructure formation below the phase transition aids in optimal conformation of the biphenyl moieties by significant distortions of their internal torsion while the modulations in l-phenylalaninate groups compensates for the former.The decrease in ADPs of atoms of A than B in high-T phase I possibly arises to optimize the short nonbonded H⋯O distances around the chiral center that is largely minimized in phase II by greater intramolecular distortions of torsional angles in the former than the later. This hypothesis is supported by the small but observable distortion of In hindsight, the observed larger mean-squared displacements of atoms of molecule 4.a  ×  b  ×  2c superstructure of 4-biphenylcarboxy-(l)-phenylalaninate at T = 100 K has been successfully described as a commensurately modulated structure within (3+1)D superspace with superspace group symmetry P21(σ10σ3)0. The single crystal to single crystal phase transition below T = 124 K drives the 3D structure directly to a locked-in twofold superstructure accompanied by significant distortion of torsional rotations within biphenyl away from coplanarity that is also a property of incommensurately modulated structure of biphenyl but with amplitudes four times smaller than the present system.The 2p-terphenyl and p-quarterphenyl. Consistent with the Tc, the maximum amplitude of torsion is also intermediate and in the order φquarterphenyl ≥ φterphenyl > φl-phenylalaninate4-biphenylcarboxy- > φbiphenyl.The phase transition temperature is significantly higher than that in biphenyl yet significantly lower than for A > φB) within the independent molecules which is governed by multiple level of competitions involving unequal van der Waals constraints in the presence of weak hydrogen bonds between the biphenyl and l-phenylalaninate moieties while the asymmetry of φ3 is determined by intramolecular nonbonded constraints between phenyl rings and amide groups.Topologically separated, conformations of both the weaker C—H⋯O bonds and stronger N—H⋯O bonds are rigid and that underlines their role in stabilizing the crystal packing in both phases. A unique property of the present polyphenyl coupled amino acid ester is the distinctively unequal torsional amplitude  of phenyl groups but preserves the conformations of intermolecular directional N—H⋯O hydrogen bonds of the high-temperature structure.The present investigation of the phase transition in the biphenylcarboxy coupled amino acid ester system also shows consequences for crystal packing where significant distortions in conjugations represented by mutual intramolecular rotations between homo aromatic groups as well as with aliphatic amide groups results in modulated π⋯π stacking arrangements  global, I_phaseII_modulated, I_phaseI, I_phaseII. DOI: 10.1107/S2052520623000215/bm5150I_phaseII_modulatedsup2.hklStructure factors: contains datablock(s) I_phaseII_modulated. DOI: 10.1107/S2052520623000215/bm5150I_phaseIsup3.hklStructure factors: contains datablock(s) I_phaseI. DOI: 10.1107/S2052520623000215/bm5150I_phaseIIsup4.hklStructure factors: contains datablock(s) I_phaseII. DOI: 10.1107/S2052520623000215/bm5150sup5.pdfDetails of structure refinements, powder X-ray di raction experiments, Figs S1-S8, Table S1-S8. DOI: 0YDiRh5cfxe2235161, 2238250, 2238251CCDC references:


The structural and elastic properties have been investigated using XRD, FTIR and ultrasonic pulse–echo techniques. The XRD patterns confirmed the amorphous nature of the samples prepared. Density and ultrasonic velocity data were used to evaluate various elastic properties. Addition of CdO gave rise to decreased density and molar volume and increased elastic moduli, micro-hardness, and Debye temperature. The FTIR analysis revealed that increasing CdO content enhances the BiO6 octahedral sites at the expense of the BiO3 and PbO4 units. This results in the formation of Pb–O–Bi(6) and Bi(3)–O–Bi(6) linkages in the glass network, which stiffen the structure and improve the elastic properties. A correlation between elastic and compositional parameters was achieved on the basis of theories and approaches in the field.Cadmium lead bismuthate glasses in the system xCdO–(1−x)[0.5PbO + 0.5Bi Lead containing glasses find a lot of applications in the field of solder glasses, table wares and optical lenses. Although Bi3+ and Pb2+ ions have the same 6s2 electronic configurations, in toxicity, bismuth is much safer than lead. Bi2O3 is suitable for forming glass with high refractive index, non-toxicity and wide transmission range1. For these reasons, Bi-based glasses can be substituted for the Pb-containing glasses. Now, bismuth-contained glass systems are applied in optical and electronic devices, mechanical sensors, and reflecting windows3.Glasses containing heavy metal oxides Bi2O3 in glasses is complicated because it is not a classical glass former. During recent years, there has been increasing interest in the synthesis, structure and physical properties of heavy metal oxide glasses containing Bi2O3 due to their high refractive index, high infrared transparency, increased third order nonlinear optical susceptibility. Due to the high polarizability and small field strength of Bi3+ ions, a glass network of BiO3 and BiO6 structural units may be built in the presence of SiO2 and B2O34. PbO has dual role in the structure of glasses, one as a glass modifier (if Pb–O is ionic) and the other as glass former 5. In a previous study6, it has been reported that Bi3+ ions can be present in the glass structure as three [BiO3]—or six [BiO6]-coordinated, existing separately or in the mixture. Meanwhile, Pb2+ ions can be present as three [PbO3]—or four [PbO4]—coordinated.The structural role of Bi7. FTIR studies of pure CdO nano-composites revealed an absorption peak around 420 cm−1, which is assigned to the Cd–O bond8. Due to their application in nonlinear optical materials, cadmium-doped glasses have attracted the attention of researchers during recent years7. Glasses from the binary CdO–B2O3 system (CdO = 50–90 mol %) were prepared by melting followed by annealing technique9. The FTIR spectra of these glasses indicated that CdO is consumed in the conversion of some BO3 groups to BO4 groups as many of alkali and alkaline earth oxides. At high CdO content, Cd2+ ions are assumed to behave as modifier besides forming CdO4 groups. Some Nd3+ doped cadmium borate glasses were prepared and characterized optically10. The absorption spectra have been analyzed on the basis of Judd–Ofelt theory. Effect of Na2O on structural and thermal properties of cadmium borate glasses has been investigated by Pavai et al.12. XRD and SEM results confirmed the amorphous nature of the glass samples, whereas the FTIR results indicated that the structural role played by Na2O and CdO ions preferentially get incorporated as modifier and former respectively. The influence of CdO and gamma irradiation on the IR absorption spectra of borosilicate glass was investigated12. The infrared results identified the presence of BO3, BO4, SiO4 structural units and B–O–Cd linkages in these glasses. Structure and properties of binary CdO–B2O3 and ternary xCdO·(50−x)MnO·50B2O3 glasses (0 ≤ x ≤ 50 mol%) were extensively studied13. The fraction of four coordinated boron atoms 14. The conversion of three-fold to four-fold coordination of boron atoms was confirmed. On the other hand, the absence of the IR absorption band at 840/cm suggests that the CdO4 structural units do not formed in these glasses.Cadmium is used as a barrier inside reactors to absorb neutrons and control nuclear fission2O3] (40 mol% ≤ x ≤ 90 mol%) have been investigated using XRD, FTIR and ultrasonic pulse-echo techniques. The basic building units in the glass network are identified and the structural changes induced by CdO addition were established. A study on the correlation between elastic and compositional parameters has also been carried out to obtain information regarding the local structure of these glasses.Elastic properties are suitable in describing the glass structure as a function of its composition and network connectivity. These properties help in assessing the mechanical strength and structure of glasses. The literature survey indicates that reports on elastic properties of glasses containing CdO are limited. In the current work, for the first time, the structural and elastic properties of cadmium lead bismuthate glasses in the system xCdO–(1−x) glasses enhances the BiO6 octahedral sites in the glass matrix at the expense of BiO3 groups. The low frequency peak at 418/cm, which was observed in all samples is may be attributed to vibrations of Cd2+ metal cations.IR spectroscopy studies were used to get essential information about the arrangement of the structural units of the glass samples. Figure Because the observed bands are very broad and asymmetric, the deconvolution process should be applied to the measured FTIR spectra to decompose each broad absorption band to deconvoluted peaks (component bands). Each peak has two characteristic parameters, which are the center (C) and the relative area (A). The center is related to some type of vibrations of a specific structural group, whereas the relative area (A) is proportional to the concentration of this structural group. Figure 2O3] glasses can be summarized as follows;6 and PbO4 units, respectively. The intensity of these peak has been observed to increase with increasing CdO.The broad band extending from 400 to 550/cm was deconvoluted to two peaks at about 428 and 476/cm, which are related to BiO23.The broad band extending from 550 to 1100/cm was deconvoluted to four peaks at about 690, 733, 831 and 916/cm. An additional absorption peak centered at 636/cm was observed only in Cd90 sample. This may be attributed to the metal–oxygen starching of CdO. The peak centered at 620/cm has been assigned to Cd–O bondsThe general characteristics of the fitted FTIR absorption spectra for the investigated xCdO–(1−x) glasses. Figure 3- and PbO4—relating absorption bands decrease whereas that of bands characterizing BiO6 units and Pb–O–Bi(6), and Bi(3)–O–Bi(6) linkages increase with the addition CdO. This may be explained by accepting the assumption that the addition of the cadmium oxide declines the formation of BiO3 and PbO4 units in favor of the formation of BiO6 units in the glass. The presence of extra BiO6 units and formation of Pb–O–Bi(6), and Bi(3)–O–Bi(6) linkages is expected to increase the compactness of the glass structure with increasing CdO content. This reflected the glass modifier role of CdO, which results in the change in the coordination number of bismuth ions from three to six. The structure of the studied glasses is assumed to be built up by BiO3, BiO6, and PbO4 structural units. These structural units are connected to each other through Pb–O–Bi, and Bi–O–Bi linkages.The most important condition for the formation of BiO29. Also, the molar volume can be preferably used to describe the network structure and the arrangement of the building units in glasses29. Table 2O3] glasses under investigation. The variation of measured and empirical densities with the molar fraction of CdO is shown in Fig. 3 with increasing the molar ratio of CdO from 40 to 90 mol%. This behavior is not only attributed to the lighter molar mass of CdO (128.41 g/mol) than that of Bi2O3 (465.96 g/mol) and PbO (223.20 g/mol) but also attributed to the relative changes in the density values between CdO (8.15 g/cm3), Bi2O3 (8.9 g/cm3) and PbO (9.53 g/cm3). The empirical density values also decreased, but with a slower rate, over the entire composition range studied. As a result The density is one of the simplest tools used to detect changes in the glass structure2O3] glasses decreased monotonically from 34.47 to 28.63 cm3/mol with increasing CdO content from 40 to 90 mol%  < Pb (1.63 nm) < Bi (1.81 nm). Moreover, the ionic radius values were 0.119 nm for Pb3 and PbO4 in favor of the presence of BiO6 structural units in the glass network. This results in the formation of Bi(3)–O–Bi(6) and Pb–O–Bi(6) linkages at the expense of Pb–O–Bi(3) linkages. The curves of the radial distribution function (RDF) obtained by the Fourier transformation for PbO–B2O3 glasses concluded that the well-separated peaks due to Pb–O and Pb–Pb correlations appear at about 0.23–0.25 and 0.40 nm, respectively34. Also, X-ray diffraction studies of binary Bi2O3–B2O3 glasses revealed two groups of Bi–O distances at about 0.19 and 0.25 nm35. In the light of these data, the formation of Bi(3)–O–Bi(6) and Pb–O–Bi(6) linkages at the expense of Pb–O–Bi(3) linkages in the present xCdO–(1−x)[0.5PbO + 0.5Bi2O3] glasses is expected to increase the compactness of their structure and decrease the molar volume.Based on FTIR data obtained, the addition of CdO declines the presence of the structural units BiOIn the present investigation, the molar volume of xCdO–(1−x)[0.5PbO + 0.5BiThe increase in the difference between glass and crystalline molar volumes with increasing CdO content in the glass confirms the amorphous nature of samples.2O3] glasses studied. One can observe from Fig. 2O3) by CdO. Also, the elastic moduli  was calculated from the relation 6 and 3 units. The 36. However, the BiO6, PbO4 and BiO3 structural units have a cross-link density of 4, 2 and 1, respectively. Thus, the presence of extra covalent bonds due to the formation of Pb–O–Bi(6) and Bi(3)–O–Bi(6) linkages at the expense of Pb–O–Bi(3) linkages is expected to increase the average cross-link density and number of network bonds per unit volume. This increases the rigidity and resists the deformation of glassy structure with increasing CdO content as evidenced by the increase in ultrasonic velocity, elastic moduli and micro-hardness.Changes in the glass structure due to addition of a network modifier and/or a network former can be directly reflected in ultrasonic velocities and elastic properties. Thus, the composition dependence of ultrasonic velocities and elastic moduli may yield information about the dimensionality and nature of bonding in the glass. The results of longitudinal and shear ultrasonic velocities measurements, along with the determined values of elastic moduli, micro-hardness, Debye temperature and Poison's ratio are listed in Table uli Fig.  and micruli Fig.  are impr37. Otherwise, it is considered in low cross-linking density materials. Three-dimensional glasses  have Poisson’s ratio values extending from 0.1 to 0.2, meanwhile, two-dimensional glasses have Poisson’s ratio values extending from 0.3 to 0.537. It can be seen from Table 2O3] glasses have Poisson’s ratio values < 3.0, which suggest that these glasses have high cross-linking density. These cross-links generate covalent bonds and resisting the transverse deformation. This evidenced the presence of PbO4, BiO3 and BiO6structural units within the matrix of these glasses.Poisson's ratio plays a dominant role in exploring the degree of connectivity and cross-link density of the glass structure. It is reported that, if the solid material has Poisson’s ratio < 0.3, then it has been counted in high cross-linking density materials2O3] glasses  by CdO. This behavior is in consistent with the results of molar volume, ultrasonic velocities, elastic moduli, and micro-hardness.Debye temperature is an important thermal parameter in the determination of elastic properties and atomic vibrations of solids. The increasing trend of Debye temperature in xCdO–(1−x)[0.5PbO + 0.5Bises Fig.  implies 38 and Rajendran et al.39 suggested bulk modulus—molar volume correlation according to the equation 2O3] glasses. The equation of the fitted curve is given by 2 = 0.963. A good bulk modulus-molar volume correlation was achieved in alkaline earth aluminoborate RO–Al2O3–B2O3  glasses 45, WO3–B2O3–MgO–TeO2 glasses (A = 0.466 and z = 0.09)46, Li2O–PbO–B2O3 glasses (A = 0.469 and z = 0.091)47 and PbO–CuO–B2O3 glasses (A = 0.473 and z = 0.094) glasses48. This supports the suitability of Abd El-Moneim’s approach44 for understanding the Poisson's ratio data of glasses.Fractal bond connectivity  and total dissociation energy per unit volume (ith oxide component dissociation energy per unit volume). The calculated 2O3] glasses are listed in Table 2O3 oxides, we have applied 3 respectively51. It was found that both 2O3) mole by mole with CdO. These results agree well with the elastic moduli  glasses can be achieved through the total theoretical packing density.In these equations, y of Eq.  for the 2O3] (40 mol% ≤ x ≤ 90 mol%) were successfully prepared and their properties are characterized using XRD, FTIR and ultrasonic pulse-echo techniques. The inclusion of CdO has linearly decreased the ultrasonic velocity, elastic moduli, micro-hardness and Debye temperature increase show a linear increase. FTIR analysis clearly suggested that CdO plays a network modifier role, whereas Bi2O3 and PbO both play the role of network formers. The presence of BiO3 and PbO4 units is declined in favor of the presence of BiO6 units as CdO content increases. This modified the structure and increased the cross-link density and rigidity of the glass. Finally, a good correlation was achieved between elastic moduli and the most significant compositional parameters, like molar volume, fractal bond connectivity, packing density and dissociation energy per unit volume.Cadmium lead bismuthate glasses in the system xCdO–(1−x)[0.5PbO + 0.5Bi


Benefiting from the synergistic effects of these strategies, the resulting VOx/Mn–V2C electrode exhibits the high capacity of 530 mA h g−1 at 0.1 A g−1, together with a remarkable energy density of 415 W h kg−1 and a power density of 5500 W kg−1. Impressively, the electrode delivers excellent cycling stability with Coulombic efficiency of nearly 100% in 2000 cycles at 5 A g−1. The satisfactory electrochemical performances bear comparison with those in reported vanadium‐based and MXene‐based aqueous ZIBs. This work provides a new methodology for safe preparation of outstanding vanadium‐based electrodes and extends the applications of MXenes in the energy storage field.As an emerging two‐dimensional material, MXenes exhibit enormous potentials in the fields of energy storage and conversion, due to their superior conductivity, effective surface chemistry, accordion‐like layered structure, and numerous ordered nanochannels. However, interlayer accumulation and chemical sluggishness of structural elements have hampered the demonstration of the superiorities of MXenes. By metal preintercalation and in situ electrochemical oxidization strategies on V 2CTx MXene. Benefiting from the enlarged interplanar spacing of MXene and the outermost raised vanadium valence, the resulting VOx/Mn–V2C electrode exhibits high specific capacity, high energy density, and longevity in aqueous zinc‐ion batteries.Dual strategies of metal preintercalation and in situ electrochemical oxidization are developed for resolving interlayer accumulation and structural‐element chemical sluggishness of V Moreover, the aqueous electrolytes used in ZIBs possess competitive ion‐transfer ability and could cancel the flammable issues caused by organic electrolytes. Consequently, aqueous ZIBs are regarded as highly promising alternative energy‐storage systems for future applications. However, it is a still formidable challenge how to design a robust and high‐efficiency cathode material which could advance the commercialization of aqueous ZIBs.In view of the ever‐increasing energy needs and environmental pollution associated with the combustion of fossil fuel, there is an urgent need to develop high energy, high security, and sustained electrochemical energy‐storage systems.1, 2 manganese oxides, organic molecules and polymers, Prussian blue analogs, and other intercalation compounds. Among these, vanadium‐based oxides with many molecular formulas and crystal structures, commonly exhibit the high theoretical specific capacity and excellent cycling stability, owing to their multiple valence states and opened‐framework crystal structure. However, insertion/extraction of Zn2+ in its crystal structure often results in intrinsic sluggish kinetics, irreversible phase transitions, and even structural collapse, leading to inferior electrochemical performances. In addition, most vanadium‐based cathodes, especially those containing vanadium oxides, exhibit low electronic and ionic conductivity, which hampers their Zn2+ storage capability. Although great attempts have been made to fabricate the vanadium‐based cathode materials for aqueous ZIBs, rational design of such materials is still in its infancy. Therefore, it is necessary to develop an applicable methodology for the preparation of the feasible vanadium‐based cathode materials with stable phase components and high electronic/ionic conductivities to improve the capacity and cycling life of ZIBs.Recently, many kinds of materials have been designed to serve as the cathodes of aqueous ZIBs. These include vanadium‐based oxides,13 man pollutant degradation, sensors, and energy storage and conversion. Equipped with nanolaminate microstructure, superior conductivity, and adequate surface chemistry, MXenes provide a great opportunity for fabrication of high‐performance ZIBs. As a member of MXene families, V2CTx possesses an accordion‐like 2D layered structure and numerous ordered nanochannels, which would be beneficial to electron transport and could provide adequate active sites for the insertion/extraction of Zn2+ ions. Unfortunately, pure V2CTx MXene delivers unsatisfactory electrochemical performances in aqueous ZIBs. It is speculated that the poor redox reactivity of V2CTx can be ascribed to its low valence V atoms and its shrinkable layer structure, which prohibits it from taking part in multielectron redox reactions and accelerating charge transfer during the charge/discharge process. Considering the classical multielectron transfer potential of vanadium, it could be possible to promote the Zn‐ion storage capability of V2CTx by raising the valence state of the vanadium atoms in V2CTx. Preferably, if the conductive 2D layered structure of V2CTx is deliberately preserved while the interplanar spacing of V2CTx is enlarged, high and fast Zn2+ storage capacities could be easily achieved in theory.Over the past decade, MXenes have grown into key versatile 2D materials that have been widely applied in photodetectors,35 pol2C (Mn–V2C) could enlarge the interplanar spacing of MXene, and simultaneously stabilize its layered structure during the charging/discharging process. The phase transformation from V2C to amorphous vanadium oxide (VOx) raises the valence states of the outermost V atoms without destroying the layered structure of the internal V2C. Thus, the aqueous ZIBs based on the resulting VOx/Mn–V2C cathode exhibit a high specific capacity of 530 mA h g−1 at the current density of 0.1 A g−1 as well as high energy density of 415 W h kg−1. More importantly, the reaction mechanism of the VOx/Mn–V2C electrode is investigated in detail and through multiple analytical methods to explore the electrochemical kinetics and Zn‐ion storage during the charge/discharge process. This study opens an effective avenue for the rational fabrication of electrode materials with high energy density and long cycling life for aqueous ZIBs.Herein, metal preintercalation into interlaminar spaces and the in situ phase transformation induced by electrochemical oxidization have been developed and have been found to enhance ion/electron transfer and the zinc‐ion storage capacity of MXene. Manganese ions intercalated into V22CTx MXene with manganese preintercalation (Mn–V2C) is shown in Figure 2CTx MXene was first obtained from V2AlC MAX by HF etching the Al layers. Subsequently, Mn–V2C was obtained by treatment of V2CTx with alkali (labeled as K–V2C) and orderly ion‐exchange strategies using potassium hydroxide (KOH) and manganese acetate aqueous solution during a liquid‐phase immersion process, respectively . The morphological evolutions of the resulting materials throughout the synthesis process were monitored by scanning electron microscopy (SEM). As shown in Figure 2AlC MAX show the typical morphology of the ceramic phase, which displays a rough surface and the typical densely layer‐stacking structure with micrometer size. V2AlC MAX can be exfoliated into V2CTx MXene with an accordion‐like multilayer nanostructure during the HF‐etching process  spectra  and high‐resolution TEM (HRTEM). As shown in Figure 2CTx offers stacking morphology to the multilayer nanosheets, in agreement with the SEM results. The interplanar spacing of V2CTx, observed from the HRTEM image is about 0.73 nm . After etching with HF, the characteristic peaks of V2AlC MAX at 13.5° and 41.3° were significantly weakened, and this is attributed to the extensive removal of Al during etching process. Meanwhile, a new broad peak appeared at 12.5° , calculated according to Bragg's Law. After the alkalization by KOH, it was observed that the (002) peak shifts to a lower angle of 9.3°  peak when compared with K–V2C  pattern of V° Figure , which a29‐0101).41 Aft° Figure , which c2AlC to V2CTx and finally, to Mn–V2C. As shown in Figure 2AlC at 254 and 354 cm−1 essentially disappeared from the spectrum of V2CTx, and new broad peaks I and II appeared at 250 and 914 cm−1, corresponding to the V—C vibrations. In addition, a broad peak III appeared in the range of 1107–1713 cm−1, and could be attributed to D and G bands of the layered structures, further confirming the successful conversion of V2AlC to V2CTx. In the spectrum of Mn–V2C, peak I becomes broader but weaker, and peak II downshifts and becomes stronger in comparison with those in V2CTx. These effects are ascribed to the breakup of partial V—V bonds and the formation in their place of a V—O—Mn bond, indicating that the Mn atoms in Mn–V2C had been successfully intercalated into V2C by forming chemical bonds between V and Mn atoms. This formation of V—O—Mn bonds in Mn–V2C is expected to stable the V2C structure during the charging/discharging processes. The electrical conductivities of Mn–V2C and V2CTx were examined by the four‐probe method on pressed pellets. They are as high as 1570 ± 50 and 1610 ± 50 S cm−1, respectively, which indicates that the high conductivity of MXene is not destroyed during the Mn‐ion preintercalation process.Raman spectra were recorded in order to investigate the structure and phase transformation from V2CTx and Mn–V2C were further studied by the X‐ray photoelectron spectroscopy (XPS). As shown in Figure 2CTx shows four peaks at 284, 516, 530, and 688 eV, which are assigned to C 1s, V 2p, O 1s, and F 1s, respectively. However, the XPS spectrum of Mn–V2C has two additional peaks at 642 and 653 eV, which correspond to Mn 2p3/2 and Mn 2p1/2, respectively. The high‐resolution C 1s XPS spectrum for V2CTx shows four peaks at 283.8, 284.8, 284.1, and 288.2 eV, which are assigned to V2C, C—C/C=C, C=O, and O—C=O, respectively . In addition, the GCD profiles of both electrodes display two pairs of plateaus during discharging/charging, which is in good agreement with the CV results.Figure s Figure . The VO−1 with a potential range from 0.2 to 1.6 V. The VOx/Mn–V2C electrode displays much higher discharge capacity and rate performance than VOx/V2CTx at various current densities  bulbs  of 99% for up to 300 cycles. The electrochemical activities are inferior to those of VOx/Mn–V2C. The specific capacity of VOx/V2CTx after the 300 cycles is as low as 167 mA h g−1, which is only 66% of the initial capacity. Due to the absence of a preintercalated cations, the layer structure of V2CTx was destroyed and the VOx formed on the surface of V2CTx could be covered during the cycling process , and electrochemical impedance spectroscopy (EIS) tests. The CV curves of the VOx/Mn–V2C‐based battery were recorded at scan rates ranging from 0.1 to 0.9 mV s−1  and scan rate (v) from CV curves, as belowɑ and b are empirical parameters, and the value of b is defined by the slope of the log i versus log v graph, as shown in the following equationThe capacity contributed by the capacitive effect and diffusion effect can be determined by the relationship between the peak current intensity  values of VOx/Mn–V2C are 9.98 × 10−8–1.02 × 10−9 cm2 s−1, which is obviously greater than those of VOx/V2CTx (8.16 × 10−9–1.48 × 10−10 cm2 s−1). The D values of VOx/Mn–V2C are comparable to those of other reported materials used in aqueous ZIBs (Figure  which indicates that VOx/Mn–V2C possesses the rapid diffusion of zinc ions. The higher D values can be attributed to preintercalated Mn2+ extending the interlayer spacing of the prepared Mn–V2C, which provide ordered channels for the rapid diffusion of Zn2+. Furthermore, owing to the existence of abundant interfaces between the superficial VOx and the residual Mn–V2C conductive framework, charge redistribution on the interface results in the weakening of electrostatic interactions. This promotes the faster electrochemical kinetics of Zn2+ insertion/extraction, and leads to a greater diffusion coefficient of Zn2+. The enhanced charge transfer and ionic diffusion ability can be also identified by EIS curves (Figure x/Mn–V2C shows the lower charge transfer resistance, which means the higher conductivity in VOx/Mn–V2C than that of VOx/V2CTx. Moreover, the EIS profiles for VOx/Mn–V2C after 300 cycles exhibit the approximate impedance to that at initial state, whereas VOx/V2CTx show the obviously increased impedance after 300 cycles, which is ascribed to the expanded interlayer spacing and stable layered structure of MXene benefited from preintercalated Mn ions during the cycling process. Therefore, the synergistic strategies of metal preintercalation and in situ electrochemical oxidization operating on MXene could enhance ion/electron transfer for aqueous zinc‐ion batteries.The diffusion kinetics of Zns Figure . During s Figure . The sma2+ ions at the fully discharged and charged states of the VOx/Mn–V2C electrodes by analyzing the differences in the valence state of the major elements, Zn, O, and V. As shown in Figure 3/2 and Zn 2p1/2, respectively, demonstrating the existence of the Zn2+ that had been successfully intercalated into the host lattice of the VOx/Mn–V2C. Subsequently, while charging to 1.6 V, the intensity of Zn 2p becomes weaker, as the extraction of zinc ions from the VOx/Mn–V2C cathodes proceeds. In the O 1s XPS spectra (Figure 2O obviously becomes weaker at fully charged states when compared to fully discharged states, indicating that the Zn2+ diffusion process in VOx/Mn–V2C is coupled with the diffusion of H2O due to the Zn2+ solvation.An ex situ XPS analysis was performed to further reveal the insertion/extraction reaction process of the Zna Figure , the fitx/Mn–V2C (Figure 5+, V4+, V3+, and V2+ signals, indicating the intrinsic mixed‐valence state of vanadium. At the fully discharged state, V4+ and V3+ are the dominant species relative to V5+. When charged fully to 1.6 V, the V4+ and V3+ signals decrease and simultaneously, the signal from V5+ increases significantly. In addition, the slight upshifting of the main peak positions to high binding energies also demonstrates the increasing average valence states of V from discharging to charging. The above results demonstrate that the Zn||VOx/Mn–V2C batteries display a battery‐type energy release/storage mechanism with the Zn2+ reaction as well as the redox of cathode materials. Notably, the V2+ signals in both states of the V 2p XPS spectra still maintain the similar status. In addition, the concentrations of Mn ions for the cathodes at the fully charged and fully discharged states are 0.93 and 0.89 wt% observed by ex situ EDS spectra (Figure x/Mn–V2C at fully charged and fully discharged states preserve well and no other impurities occur during the charge/discharge process. This indicates the structural stability of VOx/Mn–V2C cathodes, which is beneficial to the long cycling stability. In general, the reactions on the electrodes can be tentatively shown in Figure 2+ and H2O into the VOx/Mn–V2C host occurs at the cathode and is accompanied by interconversion between V5+, V4+, and V3+ in VOx, and the corresponding gain or loss of electrons from the zinc metal appears at the anode.The charging/discharging process would coincide with the valence change of the vanadium in VOC Figure . The V 2x/Mn–V2C is a promising cathode material in aqueous zinc‐ion batteries. The metal ions that are preintercalated into MXene not only enlarge the interplanar spacing of MXene, but also stabilize the layered structure of MXene, which can promote the charge/electron transfer during the charge/discharge process. The phase transformation from V2C to amorphous VOx induced by in situ electrochemical oxidation could form the heterogeneous interface between residual Mn–V2C and the newborn VOx, which may induce charge redistribution in the interface region and expedite ion or electron transport. Moreover, the in situ phase transformation could also effectively protect us from the toxicity of high valence vanadium during the preparation of materials and assembly of batteries processes. These high valence V atoms from the outermost VOx participate in reversible interconversion of V species accompanied by the insertion/extraction of Zn2+, which promises high capacities of VOx/Mn–V2C. The internal Mn–V2C MXene works as the 2D substrate which fully exposes active materials, and meanwhile effectively immobilizes VOx active species even with a great deal of cycling. These merits enhance electrochemical redox kinetics of VOx/Mn–V2C cooperatively in aqueous zinc‐ion batteries, thus promising high capacities and outstanding cycling stability.The above observations clearly demonstrate that VO32CTx, which in turn could maintain the enlarged interplanar space for frequent transfer of Zn ions during extended cycling. The phase transformation induced by in situ electrochemical oxidization from V2C into amorphous VOx raises the valence of the outermost V under the initial charging process. High‐valence V atoms in VOx undergo valence interconversion among V3+, V4+, and V5+ accompanied by the insertion/extraction of Zn2+ during the discharging/charging process, which leads to a noticeable enhancement of the Zn2+ storage capacity. Meanwhile, the inner multilayered structure of V2C is maintained intentionally, and provides abundant ordered nanochannels with inherently high electronic/ionic conductivity which supports fast electrochemical reactions. The residual 2D V2C also offers a large specific surface for deposition of VOx, fully exposing active materials and meanwhile effectively immobilizing VOx active species even after hundreds of cycles. These merits provide the VOx/Mn–V2C cathode with high capacity of 530 mA g−1 at 0.1 A g−1, and excellent cycling stability of at least 2000 cycles even at 5 A g−1. This is conclusive proof of the synergistic effects arising from functionalized strategies operating on MXene. This work offers a satisfactory and low‐toxic vanadium‐based cathode candidate for Zn‐ion storage, and the validated methodology can be used with other MXene materials to enhance ion‐transfer kinetics and electrochemical performances in energy‐storage and ‐conversion systems.In summary, we developed dual strategies of metal preintercalation and in situ electrochemical oxidization to deal with the interlayer accumulation and chemical sluggishness of structural elements in MXene used in aqueous ZIBs. The Mn ions preintercalated into the interlaminations could stabilize the layered structure of VThe authors declare no conflict of interest.Supporting InformationClick here for additional data file.


In this work, the impregnation method was employed for the preparation of the catalysts. Systematic investigations on the activity and stability of Fe‐based catalysts were carried out in a packed‐bed micro‐activity reactor at 800 °C with a feed gas flow rate of 18 mL/min. The effect of doping Y2O3, MgO, SiO2 and TiO2 over ZrO2 on the catalytic performance was also studied. BET revealed that the specific surface areas and pore volumes are increased after SiO2, TiO2, and Y2O3 are added to ZrO2 while MgO had a negative impact and hence a little decrease in specific surface area is observed. The catalytic activity results showed that the Fe‐based catalyst supported over TiO2‐doped ZrO2 that is, Fe−TiZr, demonstrated the highest activity and stability, with a maximum methane conversion of 81.3 % during 180 min time‐on‐stream. At 800 °C, a maximum initial methane conversion of 73 %, 38 %, 64 %, and 69 % and a final carbon yield of 121 wt. %, 55 wt. %, 354 wt. %, and 174 wt. % was achieved using Fe−MgZr, Fe−SiZr, Fe−TiZr and Fe−YZr catalysts, respectively. Moreover, bulk deposition of uniform carbon nanotubes with a high degree of graphitization and different diameters was observed over the catalysts.Methane decomposition is a promising route to synthesize CO Wet‐impregnated catalysts for the synthesis of hydrogen and carbon nanotubes from methane decomposition are reported in this article. The activity results in terms of methane conversion and carbon yield have shown that iron‐based catalysts supported on zirconia (Zr) modified with various oxide supports have demonstrated varying activity profiles. Catalysts supported on titania‐modified Zr remained the best‐performing catalyst. Since hydrogen produces more energy than any fossil fuel (per unit weight) and can replace fossil fuel.2 and C in a simple reaction  and tungsten oxide (WO3) to ZrO2 on the performance of Fe‐containing catalysts. They found that the catalyst‘s stability was increased by the addition of La2O3, however, the use of WO3‐ZrO2 as support material enhanced its stability significantly. The catalyst with the label 20 wt. % Fe/WO3‐ZrO2 maintained its activity for 240 min that was assigned to the stronger metal‐support interaction, that is, interaction of Fe2O3 particles with the support (WO3‐ZrO2).Zirconia‐based oxides offer acid/base properties, redox properties, and tunable phase composition that has attracted the interest of the scientific community. However, in the thermal decomposition of methane, there aren′t many studies that focus on the use of ZrO2 from crystallization at elevated temperatures that facilitates reservation of the higher specific surface area of the amorphous structure,2 support serves as a thermally stable catalyst support while effectively preserving the tetragonal ZrO2 phase.2O3 and found that the active surface area of Ni/Al2O3 increases as MgO is added to the system. The addition of MgO to the catalyst caused the growth of smaller nickel crystallites with more potent adsorption sites as a result of strong metal‐support interaction and the microstructure organization of the catalyst. The rate of methane decomposition increased during the initial stages of the reaction as the content of MgO increased.Silica is reported to prevent ZrO2 has poor thermal stability and a low specific surface area. In addition, under high‐temperature and high‐pressure conditions, the surface area of TiO2 would drastically decrease.2−ZrO2 has attracted more attention as catalyst support because of the high specific area and high thermal stability compared to the relative single oxide. The addition of titanium to zirconium not only increases the specific surface area and thermal stability but also improves the acidity and basicity of zirconium and titanium.TiO2O3, MgO, SiO2, and TiO2) was developed and reported in this work. The fresh and spent catalysts are characterized to justify the findings using different techniques such as BET, H2‐TPR, O2‐TPO, XRD, TGA, and TEM.The objective of this study is to develop a Fe−Zr catalyst with high activity and stability for the catalytic decomposition of methane. For this purpose, the catalytic performance of Fe−Zr with different additives  and an average pore size of 5.35 nm, which is beneficial in the metal additive‘s dispersion at high loading.The textural characteristics of the as‐synthesized catalysts were evaluated using N, Ti, Y) is increased after SiO2, TiO2, and Y2O3 are added except Fe−MgZr that shows a little decrease. Nevertheless, the Fe−SiZr sample shows the highest surface area (127.2 m2/g) and lowest pore size (5.35 nm), while the Fe−MgZr sample displays the lowest surface (19.1 m2/g) and highest pore size (36.3 nm). The surface area of the unmodified Fe−Zr catalyst is 20.2 m2/g and remarkably increased to 22.8 m2/g and 50.9 m2/g for Fe−TiZr and Fe−YZr catalysts, respectively. Also, the pore volume of Fe−TiZr is found to be 0.173 cm3/g, which is higher than that of the unmodified Fe−Zr (0.157 cm3/g).Compared with Fe−Zr, the specific surface area and pore volume of Fe‐mZr  and rhombohedral Fe2O3 phases . Fe−SiZr catalyst has only rhombohedral Fe2O3 phases. Fe−YZr catalyst has rhombohedral Fe2O3 phases, tetragonal yttrium zirconium oxide phases  and Rhombohedral yttrium zirconium oxide phases . Typically, this behavior showed that the addition of Y2O3 had a significant impact on the phase composition of the zirconia support. Thus, we can infer that rather than the monoclinic ZrO2 (m‐ZrO2) phase, the growth of the tetragonal zirconium phases (t‐ZrO2) phase was enhanced by the addition of Y2O3. The degree of crystallinity of the zirconia‐supported Fe catalyst was calculated to be 12 %, 10.3 % and 10.2 % for the Fe−TiZr, Fe−YZr and Fe−Zr catalysts respectively. Moreover, the low intensity of the Iron peaks in the Fe−TiZr and Fe−YZr catalysts further confirms its fine surface dispersion on the catalyst support.Powder XRD was conducted to study the crystal structures of the Fe‐loaded samples. The XRD patterns of zirconia‐supported Fe catalysts are presented in Figure 2‐TPR (Temperature‐programmed reduction) is an important technique for characterizing the catalyst‘s metal‐support interactions and reducibility. It may also be used to verify the catalyst‘s appropriate reduction temperatures.2‐TPR curves of the fresh catalysts are shown in Figure 2O3 to Fe3O4. The unmodified and SiO2 modified samples showed identical profiles in terms of intensity and position, however, the rest of the modified samples displayed lower intensities, particularly MgO and TiO2 modified samples, and their peaks are slightly shifted to higher temperatures denoting stronger interactions. The broad peaks between 550 and 750 °C could be assigned to the further reductions of Fe3O4 to FeO, and Fe. The addition of modifiers diminished the intensities with respect to the unmodified sample. The peak for Y2O3 modified sample exhibited the highest intensity, while the rest of the modified samples exhibited similar intensities. At around 800 °C temperature, a weak H2 consumption peak appeared related to the Fe−TiZr sample. This could be attributed to the reduction of mixed oxide species to metallic species.The H2O3 particles were significantly smaller and much more separated, which further confirmed the greater dispersion associated with active Fe2O3 on surface of TiZr support  on the methane conversion for 180 min time on‐stream (TOS) using 30 wt. % Fe supported on ZrO2 catalysts. The results exhibited that the Fe−TiZr sample gave the highest conversions of methane at about 81.3 % and kept increasing over the period of the investigation (3 h). In contrast, Fe−MgZr, Fe−SiZr, and Fe−Zr catalysts began with initial CH4 conversions of about 74 %, 38 % and 50 % respectively, but suffered fast deactivation to attain as low values as 29 %,17 % and 11.5 %, respectively after running 180 min of TOS  in the catalyst structure led to an increase in its catalytic activity. However, its activity decreased with time to about 50.1 % due to carbon deposition on active Fe surfaces.A high methane conversion of about 69 % was achieved in the Fe−YZr catalyst at the temperature of 800 °C. The addition of yttria .−1 is assigned to the disordered carbon, including amorphous carbon or defective graphite sheets. On the contrary, the G band peaks at around 1580 cm−1 correspond to C−C stretching vibrations that are characteristic of graphite.D/IG is widely used to express the degree of graphitization for the carbon, that is, the lower the ID/IG ratio, the higher the crystalline order of the carbon species. The ID/IG values of all samples means that the carbon is ordered, with minor contributions from disordered particles.D/IG are different, indicating that the deposited carbon on Fe−TiZr and Fe−YZr catalysts had less graphitization degree than other zirconia‐supported Fe catalysts, which is in accordance with the formation of more carbon on the surface of Fe−TiZr catalysts.Raman spectra of the used catalysts are presented in Figure [18] The dark spots shown in Figure The microstructural changes and morphology of the deposited carbon over the most active Fe−TiZr catalyst at 800 °C reaction temperature and 3 h time on stream were studied by SEM and TEM analysis and the images are shown in Figures 2, TiO2, and Y2O3. From the results of catalyst activity, TiO2−ZrO2 incorporated is found to be an excellent support for Fe‐based catalyst towards CH4 decomposition reaction on time on stream, the catalytic performance of the Fe−MgZr catalyst drops fast than Fe−YZr catalyst. Even after 180 min, CH4 conversion over Fe−YZr catalyst does not drop below 50 %. It is also found that the Fe−TiZr catalyst was more stable than other zirconia‐supported catalysts and it could be responsible for the highest carbon yield over the Fe−TiZr catalyst, even it showed low surface area. The high stability of the titanium‐supported catalyst could be attributed to the formation of nanosized active Fe and its fine dispersion on the titanium zirconia matrix after the reduction of spinel solid solution.This work reports wet‐impregnated Fe‐based zirconia‐supported catalysts for catalytic decomposition of methane. Zirconia was modified by doping with metal oxides including MgO, SiO3)3 ⋅ 9H2O, purity 99 %, laboratory reagents & fine chemicals). Millipore system of water purification was used to obtain ultrapure water.Zirconium oxide and other oxide used were obtained from DAIICHI KIGENSO KAGAKU KOGYO CO., LTD. OSAKA – JAPAN. The precursor for iron was ferric nitrate nonahydrate  equipped with a thermal conductivity detector. The conversion of methane (XCH4) and Carbon yield were calculated using following Equations (2) and The testing of as‐synthesized catalysts was conducted at a reaction temperature of 800 °C at 1 bar pressure using a fixed‐bed tubular reactor purchased from PID Eng & Tech. Firstly, glass wool was placed into the reactor to serve as the catalyst bed over which 0.15 g of catalyst was loaded. A K‐type thermocouple was axially located in the reactor to measure the temperature of the catalyst bed during CDM. The fresh catalyst was reduced under hydrogen for 1 h at 800 °C prior to flowing reaction gas. The gaseous feedstock containing 12 mL/min of CHCH4,inis methane in the feed, CH4,outis methane in the product, WP is the products weight after reaction and Wcat is the weight of the fresh catalyst.Where The textural properties of the as‐synthesized catalysts were measured using a Micromeritics Tristar II 3020 analyser at 77 K. Prior to porosity analysis, drying/degassing of each catalyst was conducted at 250 °C for 3 h under nitrogen to remove any surface impurities. Barret‐Joyner‐Halenda (BJH) method was utilized for evaluating the pore volume of the catalysts.The chemisorption equipment purchased from Micromeritics (Auto Chem II 2920) was utilized for temperature‐programmed reduction (TPR) and oxidation (TPO). The catalysts were subjected to temperatures variation between 50 and 900 °C under a mixture of 10 % hydrogen in argon flowing at 2.40 L/h for the TPR analysis while 10 % hydrogen in argon was replaced with 10 % oxygen in helium for TPO analysis of type of carbon formed during CDM.X‐ray diffraction profiles of as‐synthesized catalysts were measured using a Miniflex Rigaku diffractometer containing Cu K as source of X‐rays. The diffractometer was operated at 40 mA and 40 kV.−1 were later processed via Spectra Manager Ver. 2 software.Laser Raman (NMR‐4500) Spectrometer  was used to evaluate the type of carbon formed during CDM. The spectrometer used a 532 nm wavelength excitation beam with an objective lens capable of 100×magnification as well as 1.6 mW of laser intensity. Three exposures within 10 seconds were averaged to collect each spectrum. Spectrometer recordings within Raman shift of 1200–3000 cmThe quantity of carbon deposits on the spent catalysts was measured using TGA analysis. In a typical analysis, 10–15 mg of the spent catalysts was subjected to thermal variation ranging from 50 to 1000 °C at a ramp rate of 20 °C/min under oxidative environment. Finally, the weight loss with respect to temperature was monitored.2−ZrO2 catalyst and Table S1, showing quantitative result of the 30 %Fe/10 % TiO2−ZrO2 catalyst.The Supporting Information contains Figure S1, an EDX image of 30 %Fe/10 %TiOThe authors declare no conflict of interest.1As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re‐organized for online delivery, but are not copy‐edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors.Supporting InformationClick here for additional data file.