Background:Plasmodium vivax remains the malaria species posing a major threat to human health worldwide owing to its relapse mechanism. Currently, the only drugs of choice for radical cure are the 8-aminoquinolines (primaquine and tafenoquine), which are capable of killing hypnozoites and thus preventing P. vivax relapse. However, the therapeutic use of primaquine and tafenoquine is restricted because these drugs can cause hemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency. This study aimed to assess and understand the hemolytic risk of using 8-aminoquinolines for radical treatment in a malaria endemic area of Thailand.Methods: The prevalence of G6PD deficiency was determined using a quantitative test in 1,125 individuals. Multiplexed high-resolution meltinging (HRM) assays were developed and applied to detect 12 G6PD mutations. Furthermore, biochemical and structural characterization of G6PD variants was carried out to understand the molecular basis of enzyme deficiency.Results: The prevalence of G6PD deficiency was 6.76% , as assessed by a phenotypic test. Multiplexed HRM assays revealed G6PD Mahidol in 15.04% (77/512) of males and 28.38% (174/613) of females, as well as G6PD Aures in one female. G6PD activity above the 30% cut-off was detected in those carrying G6PD Mahidol, even in hemizygous male individuals. Two variants, G6PD Murcia Oristano and G6PD Songklanagarind + Viangchan, were identified for the first time in Thailand. Biochemical characterization revealed that structural instability is the primary cause of enzyme deficiency in G6PD Aures, G6PD Murcia Oristano, G6PD Songklanagarind + Viangchan, and G6PD Chinese 4 + Viangchan, with double G6PD mutations causing more severe enzyme deficiency.Conclusion: In western Thailand, up to 22% of people may be ineligible for radical cure. Routine qualitative tests may be insufficient for G6PD testing, so quantitative tests should be implemented. G6PD genotyping should also be used to confirm G6PD status, especially in female individuals suspected of having G6PD deficiency. People with double G6PD mutations are more likely to have hemolysis than are those with single G6PD mutations because the double mutations significantly reduce the catalytic activity as well as the structural stability of the protein. P. vivax remains the predominant species in many areas, including Thailand. Vivax malaria has a relapse mechanism caused by the dormant liver stage (hypnozoite), resulting in the parasites reappearing months or even years after initial infection  deficiency  reported approximately 241 million malaria cases in 2020, with 765,000 deaths . P. vivanfection . Consequ malaria . The druP. vivax . They arficiency . G6PD isficiency . Furtherficiency .The hemolytic toxicity of 8-aminoquinolines is determined by two major factors: oxidative stress exposure (exposure time and level of oxidative stress) and the G6PD enzyme activity level in RBCs. The level of oxidative stress is determined by the dose regimen, whereas G6PD enzyme activity is determined by the G6PD genotype. Drug-induced hemolysis in G6PD deficiency was found to be dose-dependent for 8-aminoquinolines . The staBecause of the adverse events that can be caused by 8-aminoquinolines, G6PD testing is recommended by WHO when available before radical cure . G6PD acP. vivax was the most common causative species with a 97% incidence rate . G6PD genotyping was performed using a developed multiplexed high-resolution melting (HRM) analysis that can detect 12 G6PD mutations common in Southeast Asia, allowing for high-throughput G6PD genotyping. Furthermore, to provide insight into the molecular mechanisms underlying enzyme deficiency of G6PD variants, the biochemical and structural characteristics of four G6PD mutations  were described.The purpose of this study was to determine the prevalence and genotypes of G6PD deficiency in western Thailand, a malaria endemic area, for the purpose of assessing and understanding the hemolytic risk of using 8-aminoquinolines for radical cure of A total of 1,125 blood samples were collected in ethylenediaminetetraacetic acid (EDTA) tubes and stored at −20°C until use. The participants were healthy residents living in western Thailand, along the Thai-Myanmar border. Malaria status and anemia were not tested before recruitment. For the validation of HRM assays, blood samples were collected from healthy Thai volunteers at the Faculty of Medicine Ramathibodi Hospital, Bangkok, Thailand. The integrity of samples for phenotypic analysis was maintained under these storage conditions .2, 500 μM glucose-6-phosphate (G6P), 100 μM NADP+, and 100 μM WST-8 . The enzymatic reaction was monitored by following the absorbance at 450 nm using a microplate reader . A reaction mixture set up in the absence of substrates was used for background subtraction. Hemoglobin concentration was measured using Drabkin’s reagent (Sigma-Aldrich), following the manufacturer’s instructions. The G6PD enzyme activity was expressed as units (U) per gram of hemoglobin (gHb).The blood was mixed with the reaction mixtures containing 20 mM Tris-HCl pH 8.0, 10 mM MgClDNA extraction was performed using the QIAamp DNA Blood Mini Kits , following the manufacturer’s instructions. For DNA extraction, 100 μl blood sample was used and eluted into a final volume of 100 μl. DNA concentration was measured using a NanoDrop 2000 spectrophotometer .Tm). To maximize the sensitivity and specificity of the assay, several assay conditions, including primer concentrations, assay protocol, and detection conditions were optimized . The bacteria were cultured at 37°C with 250 rpm shaking in the presence of 50 μg/ml kanamycin until the OD600 reached one and the G6PD expression was induced with 1 mM IPTG. Cells were then cultured for 20 h at 20°C with 200 rpm shaking before being harvested by centrifugation.To investigate the molecular mechanisms underlying enzyme deficiency of G6PD variants, biochemical and structural characterization were carried out. G6PD mutations were created by site-directed mutagenesis using pET28a-G6PD WT as a template and the presence of desired mutations was confirmed by DNA sequencing. Primers used for site-directed mutation are listed in Protein purification was carried out using immobilized metal affinity chromatography in accordance with the previously described protocols . Protein2, 500 μM G6P, and 100 μM NADP+. The enzymatic reaction was monitored by following the formation of NADPH at 340 nm using UV-VIS spectrophotometer . To determine the Km for G6P, the concentration of NADP+ was fixed at 100 μM while varying the concentrations of G6P from 2.5 to 1,000 μM, and to determine the Km for NADP+, the concentration of G6P was fixed at 500 μM while varying the concentrations of NADP+ from 1 to 200 µM.To assess the effect of mutations on the catalytic activity of G6PD variants, steady state kinetic parameters were determined. The standard reaction contained 20 mM Tris-HCl pH 8.0, 10 mM MgClTo examine the effect of mutations on the secondary structure of G6PD variants, the secondary structure was analyzed using circular dichroism (CD). Far UV-CD spectra of the G6PD variants (0.1 mg/ml) were recorded in a 1-mm path-length quartz cuvette at 25°C using a Jasco spectrometer, model J-815, equipped with a Peltier temperature control system. The CD spectra were collected over a wavelength range of 190–260 nm at a scan rate of 50 nm/min. Five scans were averaged for each sample, and the results of the buffer scans were subtracted.+, which is known to stabilize the G6PD protein structure, was investigated by incubating the protein with various concentrations of NADP+ . The Tm of each G6PD variant was calculated and defined as the temperature at which half of the protein was unfolded.To investigate the effect of mutations on structural stability, each G6PD variant was subjected to thermal stability analysis and their susceptibility to guanidine hydrochloride (Gdn-HCl) treatment and trypsin digestion were determined. Thermal stability testing was performed in a 20-μl reaction, containing protein at a concentration of 0.25 mg/ml mixed with 5 × SYPRO™ Orange Protein Gel Stain . The reaction mixtures were heated in a Light- Cycler 480 real-time PCR machine  at temperatures ranging from 20°C to 80°C, with excitation and emission wavelengths of 465 and 580 nm, respectively. Furthermore, the effect of NADP+  at 37°C for 2 h. The residual enzyme activity was measured and expressed as a percentage of the activity of the same enzyme incubated without Gdn-HCl.To investigate the structural stability of G6PD variants upon chemical denaturation, the protein was treated with different concentrations of Gdn-HCl (0–0.5 M) in the presence of various concentrations of NADP+ . The residual enzyme activity was measured and expressed as a percentage of the activity of the same enzyme incubated without trypsin.Finally, to determine the susceptibility of G6PD variants to trypsin digestion, the protein was treated with trypsin (0.5 mg/ml) for 5 min at 25°C in the presence of various concentrations of NADPScreening of G6PD deficiency was initially accomplished by performing a phenotypic enzyme activity assay (WST-8). The average G6PD activity among 1,125 samples was 13.32 ± 5.97 U/gHb, with male participants showing an average G6PD activity of 12.81 ± 6.65 U/gHb and female participants showing a slightly higher average G6PD activity of 13.74 ± 5.30 U/gHb. The adjusted male median (AMM) was determined to be 13.1 ± 6.5 U/gHb for the studied population and was defined as 100% G6PD activity . AccordiThe frequency distribution of G6PD activity, as determined using the WST-8 assay, for the 1,125 samples is presented in β-Actin serving as an internal control. Reaction 1 detects G6PD Gaohe (A95G), G6PD Mahidol (G487A), G6PD Viangchan (G871A) and G6PD Canton (G1376T); reaction 2 detects G6PD Aures (T143C), G6PD Chinese 4 (G392T), G6PD Mediterranean (C563T) and G6PD Chinese 5 (C1024T); and reaction 3 detects G6PD Songklanagarind (T196A), G6PD Valladolid (C406T), G6PD Coimbra (C592T) and G6PD Union (C1360T). The assays were validated with 100 normal and 100 G6PD-deficient samples, using DNA sequencing as a reference test. The HRM assays were 100% sensitive [95% confidence interval (CI): 96.30%–100%] and 100% specific (95% CI: 96.30%–100%) for detecting these 12 mutations. Among the 100 G6PD-deficient samples used for validation, three double mutations were detected which included G6PD Mahidol + Canton (G487A + G1376T), G6PD Chinese 4 + Viangchan (G392T + G871A) and G6PD Songklanagarind + Viangchan (T196A + G487A). In addition, G6PD Murcia Oristano (A209G) was discovered for the first time in G6PD-deficient samples from the Thai population, using DNA sequencing.Multiplexed HRM assays were designed to detect 12 mutations common in Southeast Asia over three reactions, with When multiplexed HRM assays were used to detect 12 mutations, we found that 22.40%  of the studied population carried a G6PD mutation. These mutations were detected in 15.04% (77/512) of the male participants and in 28.55% (175/613) of female participants. G6PD Mahidol was the predominant G6PD variant in the studied population, accounting for 99.60% of detected mutations (251/252). Another variant discovered in our study population was G6PD Aures, which was found in a heterozygous female participant with a G6PD enzyme activity level of 11.2 U/gHb. There were two male participants who had low enzyme activity (3.3 and 4.1 IU/gHb) but no G6PD mutation detected by our HRM assays. These two samples were amplified for G6PD and sent for DNA sequencing. It was revealed that both of them carried G6PD Kaiping (G1388A). The G6PD activity levels of samples with detected mutations and of samples with no detected mutations (nonvariant) are depicted in The distribution of G6PD activity levels by mutation type is presented in In the present study, one single variant (G6PD Murcia Oristano) was discovered for the first time in Thailand, as was a double variant (G6PD Songklanagarind + Viangchan). While many G6PD variants have been extensively studied, the biochemical properties of two single G6PD variants (G6PD Aures and G6PD Murcia Oristano) and two double G6PD variants (G6PD Chinese 4 + Viangchan and G6PD Songklanagarind + Viangchan) have never been reported. Therefore, biochemical and structural characterizations were carried out on these G6PD variants to better understand the molecular mechanisms underlying enzyme deficiency.+). In terms of catalytic efficiency (kcat/Km), the Class III single variants exhibited approximately 2‒ and 3‒fold lessened amounts of G6P and NADP+ catalysis, respectively. The double G6PD variants, in contrast, had significantly lower catalytic efficiencies. The catalytic efficiency toward G6P and NADP+ catalysis was approximately 22‒ and 46‒fold lower for G6PD Songklanagarind + Viangchan, respectively, and was 27‒ and 40‒fold lower, respectively, for G6PD Chinese 4 + Viangchan, when compared with that for the G6PD WT.Four G6PD variants were purified to homogeneity using immobilized metal affinity chromatography  and theiα-Helical protein. G6PD Murcia Oristano was the only G6PD variant with an absorption intensity similar to that of WT G6PD, but it had a slight difference in the intensity of its β absorption (a positive band between 195 and 200 nm). Each of the G6PD variants exhibited an absorption pattern similar to that of G6PD WT, but with varying intensities. A change in absorption intensity indicates an alteration in the flexibility or rigidity of the secondary structure. Overall, the mutations studied here had no effect on the G6PD protein secondary structure of the G6PD variants, they altered only the flexibility of the secondary structure.The effect of mutations on the structural stability of G6PD variants was investigated. First, the effect of mutations on the secondary structure was evaluated by recording the CD spectra of four G6PD variants in the range of 190–260 nm and comparing them to the G6PD WT . Human GTm of each G6PD variant was determined and compared with that of the WT enzyme  was significantly lower than that of the G6PD WT, with Tm values of approximately 11°C–14°C lower. The structural NADP+ in the human G6PD protein structure is important for protein stability. In agreement with that, the presence of 10 and 100 µM NADP+ increased the Tm values of all G6PD proteins, improving protein thermostability.The thermostability of G6PD variants was then evaluated to determine how the mutations affected the G6PD structural stability as temperature increased. The T enzyme . Except 1/2, with a higher C1/2 value indicating greater resistance to denaturation and thus greater structural stability. Under all tested conditions (in the absence and presence of 10 and 100 µM NADP+), all G6PD variants were structurally less stable than the G6PD WT, with double G6PD mutations having a greater effect on structural stability than the single G6PD mutations, as evidenced by lower C1/2 values  in the absence of NADP+, whereas the presence of NADP+ appeared to more strongly improve the structural stability of G6PD Songklanagarind + Viangchan than that of G6PD Chinese 4 + Viangchan. The C1/2 values of Songklanagarind + Viangchan and Chinese 4 + Viangchan were 0.11 and 0.06 M, respectively, in the presence of 10 µM NADP+, and 0.16 and 0.10 M, respectively, in the presence of 100 M NADP+.Protein unfolding upon treatment with chemical denaturant can be used to assess structural stability. G6PD variants were exposed to varying concentrations of the chemical denaturant Gdn-HCl, and the concentration at which the protein lost half of its activity was defined as C2 values . In agre+, all tested G6PD proteins lost 80%–100% of their activity, with G6PD Murcia Oristano (22%) retaining more residual activity than the WT enzyme (11%). G6PD Songklanagarind + Viangchan retained 3% of its activity, whereas G6PD Aures and G6PD Chinese 4 + Viangchan completely lost their activities, indicating that these G6PD variants had the lowest protein stability. At both tested concentrations (10 and 100 µM), NADP+ was found to stabilize protein structure by increasing the residual enzyme activity of all G6PD proteins. The stabilizing effect of NADP+ was the most pronounced in G6PD Songklanagarind + Viangchan, where the presence of 10 and 100 µM of NADP+ retained 64% and 76%, respectively, of G6PD activity.To further evaluate the structural stability of G6PD variants, the enzymes were treated with trypsin, and the residual enzyme activity was measured . In the The risk of hemolysis in people with G6PD deficiency has restricted the use of 8-aminoquinoline for the radical cure of vivax malaria. To identify those who are eligible for radical treatment with 8-aminoquinolines, it is critical to assess the hemolytic risk, which can be done by determining the prevalence and genotype of G6PD deficiency. Treatment with primaquine is recommended at a dose of 15 mg/day for 14 days in G6PD-normal individuals and at a dose of 0.75 mg/kg for 8 weeks in G6PD-deficient persons . In contP. vivax has been responsible for more than 90% of total malaria cases, necessitating the use of 8-aminoquinolines for radical cure  were also found to have enzyme activity levels of greater than 30% (Malaria hotspots are located along the western region of Thailand where cal cure . Previoucal cure . Here, wcal cure . Thus, acal cure . The phecal cure . People than 30% . Importathan 30% . Female than 30% .P. vivax is responsible for nearly 20% of malaria cases in the Arab world (G6PD Aures was identified by multiplexed HRM assays in a heterozygous female participant with a G6PD activity level of 11.2 U/gHb, which is greater than the 30% cut-off. The Aures mutation is common in Arab countries, but it was first reported in Thailand in 2018 and is common among Lao Theung people . Concernab world . G6PD Auvia DNA sequencing in these two samples. Although our multiplexed HRM assays can correctly identify 12 G6PD variants, they are unable to detect the zygosity of the samples and may not be suitable for G6PD genotyping in other regions owing to the variable prevalence of G6PD mutations. With simple design and easy interpretation, our HRM assays can be optimized, and the desired G6PD mutations can be included to enable G6PD genotyping in other areas. In fact, previous studies using different designs and more complicated result analyses demonstrated that HRM assays can detect zygosity in samples (The phenotypic test revealed two samples with deficient G6PD activity but no mutations detected by our HRM assays. G6PD Kaiping, which was not included in our assays, was discovered  samples ; howeverKm for the NADP+ substrate. The Tyr70Cys mutation in G6PD Murcia Oristano slightly altered the flexibility of the secondary structure and the protein structural stability. The Murcia Oristano mutation appeared to have a milder effect compared with the Aures and Mahidol mutations, implying a lower risk of hemolysis. However, more clinical data are required to confirm this assumption.Through DNA sequencing, we discovered G6PD Murcia Oristano and the double mutant G6PD Songklanagarind + Viangchan for the first time in Thailand from validated samples. HRM assays were also able to identify another double mutant, G6PD Chinese 4 + Viangchan. G6PD Murcia Oristano was previously reported among Spanish people and was classified as class III variant . In thisMultiple mutations were previously shown to have a greater effect on G6PD deficiency than single mutations . The comP. vivax (Determining the safety of radical treatment with 8-aminoquinolines is an important issue before drug administration, particularly in areas where G6PD deficiency is common. Drug administration without G6PD testing has caused medical complications in the management of hemolysis, which may have a negative impact on the patient as well as inciting public concern . When G6P. vivax . TherefoInformation on the prevalence of G6PD deficiency is useful to estimate those who are eligible to receive 8-aminoquinolines for radical treatment. With a sample size of 1,125 people, our findings suggest that up to 22% of people in western Thailand may be ineligible. Furthermore, people with the Mahidol mutation had G6PD activity that was greater than the 30% cut-off, and heterozygous female individuals had G6PD activity that was comparable to that of G6PD-normal persons. This meant that routine qualitative tests could misclassify these individuals as G6PD normal, putting them at a significant hemolytic risk when 8-aminoquinolines are prescribed. In regions where class III variants with mild enzyme deficiency are common, our findings suggest that the G6PD status should be assessed quantitatively, especially before the administration of tafenoquine. Furthermore, G6PD genotyping should be used in conjunction with hemolytic risk assessment in those suspected of having G6PD deficiency, particularly in female patients. Individuals with double mutations are more likely to have hemolysis than are those with single mutations, according to our biochemical data, because the double mutations significantly reduce catalytic activity as well as the structural stability of the G6PD protein.


In powder or solid form, it is highly effective in inactivating bacteria, fungi, and viruses while leaving mammalian tissue unaffected. The purpose of this study was to serially assess the antiviral efficacy of Si3N4 against SARS-CoV-2 using powders, solids, and embedded nonwoven fabrics. Si3N4 powders and solids were prepared using conventional ceramic processing. The “pad-dry-cure” method was used to embed Si3N4 particles into polypropylene fibers. Fabric testing was subsequently conducted using industrial standards—ISO 18184 for antiviral effectiveness, ASTM F2299 and EN 13274-7 for filtration efficiency, EN 14683 for differential pressure drop, and ISO 18562-2 for particle shedding. A modification of ISO 18562-3 was also employed to detect ammonia release from the fabric. Antiviral effectiveness for Si3N4 powders, solids, and embedded fabrics were 99.99% at ≤ 5 min, ~ 93% in 24 h, and 87% to 92% in 120 min, respectively. Results of the standard mask tests were generally within prescribed safety limits. Further process optimization may lead to commercial Si3N4-based masks that not only “catch” but also “kill” pathogenic microbes.Medical-grade masks and N95 respirators containing non-woven fibers are designed to prevent the spread of airborne diseases. While they effectively trap respiratory droplets and aerosols, they cannot lyse entrapped pathogens. Embedded antimicrobial agents such as silver, copper, zinc, iodine, peptides, quaternary ammonium salts, or nanoparticles have been used to overcome this limitation. However, their effectiveness remains debatable because these materials can be toxins, allergens, irritants, and environmental hazards. Recently, silicon nitride (Si Traditional woven fabric is made from natural yarns ; but today, synthetic or blended fibers  is an alternative to these compounds. It is a US FDA cleared implantable biomaterial that has already passed a rigorous series of ISO-10993 human biocompatibility tests [3N4 would not only trap viral droplets and particles, but also render them harmless. Incorporating this “catch and kill” mechanism into masks and their use by both the healthcare community and the general population could provide enhanced protection against the spread of respiratory disease. Therefore, the purpose of this study was to develop methods for embedding Si3N4 particles into hydrophobic polypropylene (PP) nonwoven fabric as an incorporated layer within a protective breathable mask, and subsequently test the efficacy of this fabric in inactivating SARS-CoV-2. This study was conducted in four phases: (1) The antiviral effectiveness of Si3N4 powder was first tested against a surrogate virus of lower pathogenicity ; (2) Antiviral tests using Si3N4 powder were then performed against the alpha variant of SARS-CoV-2. Concurrent testing was also conducted using solid Si3N4 discs; (3) Si3N4-embedded nonwoven fabrics were then prepared and assessed for their antiviral effectiveness; and (4) Prototype masks or representative swatches were subjected to standard industrial tests for filtration efficiency, particle permeability and shedding, breathability, and chemical release. The results of this study demonstrated that Si3N4 powder, solids, and embedded fabrics were effective in reducing live SARS-CoV-2 virions by ~ 90% to 99.99% depending on Si3N4 type, concentration, and incubation time; and the other standard tests showed that Si3N4 prototype masks performed within permissible safety limits.Silicon nitride , sintered Si3N4 discs, and PP nonwoven fabric embedded with the two Si3N4 powders. Virogenic solutions  without Si3N4 powder, non-embedded PP fabric, and polyetheretherketone (PEEK) discs were used as controls.Test materials utilized in the study consisted of two Si2 powder was nominally 90 wt% Si3N4 , 6 wt% yttrium oxide  and 4 wt% aluminum oxide . Preparation of this powder involved mixing and spray-drying of these raw materials, followed by a sequential series of firing operations including binder removal , then densification in separate pre-sinter, sinter, and hot-isostatic pressing operations at temperatures between 1400 °C and 1750 °C for times of up to 3 h and N2 pressures of between 7 kPa and 200 MPa [4 powder was prepared without sintering additives; it was only subjected to air-firing . Its particle size distribution is shown in Fig. The composition of the AP 200 MPa . Between3N4 discs (Ø12.7 × 1 ~ 2 mm) were produced using the same raw material composition as AP2 powder. They were machined from green-pressed blanks, pre-sintered, sintered, and hot-isostatically pressed [2 blasted, ultrasonically cleaned, and re-fired . Spunbond and melt-blown PP fabric was provided by O2TODAY™, . They had nominal weights of 45 and 50 g/m2, respectively. The PEEK discs (Ø12.7 mm × 1 mm) were machined from rod stock provided by McMaster-Carr .The Si pressed . After f2 Si3N4 powder were performed against two human coronaviruses—the minimally pathogenic β-CoV, OC43 (obtained from ATCC) and the highly pathogenic SARS-CoV-2 . For the OC43 tests, the Si3N4 powder was measured into Eppendorf tubes so that at 1 mL it would be either 7.5 or 15 wt%/vol. The OC43 virus was pre-prepared in a virogenic solution at a final TCID50 concentration of 7.34 × 107/mL. The Eppendorf tubes were placed in an end-over-end tube rotator for specified periods . After incubation, supernatants were extracted and passed through a 0.45 µm filter, and TCID50 assays were conducted in accordance with procedures by Smither et al.[3N4. For the SARS-CoV-2 studies, the same procedure as described above was employed except that the initial TCID50 concentration was set to 3.16 × 106/mL.Antiviral assays using APer et al.. Vero E63N4 and PEEK discs, respectively. The discs were cleaned, disinfected, and sterilized by wiping with 70% ethanol. Both test and control specimens were analyzed for infectious virus titers immediately after inoculation, and after contacting the test discs for the specified time points  at room temperature. Triplicate samples were used for all measurements. Virus-containing supernatants, at a concentration of 3 × 105 TCID50/ml, were applied to each disk. At the specified time points, media was removed to a new tube and a series of 4–1 mL washes was performed. All the media was mixed into the tube and the viral titer was determined by TCID50 assays.Testing of solid disc surfaces was performed as specified in ISO 21702. As indicated previously, the test and control materials were Ø12.7 mm as-fired Si3N4-embedded fabric was based on the “pad-dry-cure” method [2 and AP4 Si3N4 powders were utilized. Pre-treatment of the PP fabric was necessary due to the fibers’ highly hydrophobic nature. For the AP2 powder, this involved pre-rinsing the fabric under mechanical agitation in deionized (DI) H2O  followed by addition and adsorption of a surfactant  for 30 ≤ t min ≤ 90. The fabric was oven dried  and spray-coated with ~ 5 vol% aqueous slurry of AP2 Si3N4, followed by immersion and sonication in the AP2 slurry . The fabric was wrung of excess slurry, oven dried , and cured between heated weighted plates . To remove non-adherent Si3N4 particles, the fabric was washed using 1 vol% Triton X-100  under sonication  and rinsed in clean DI H2O five times followed by ~ 30 s compressed air blow-out (690 kPa). To increase powder loading, this entire procedure following fabric pre-treatment with DTAB was repeated. The post-processing net mass gain of three sampled swatches, shown in Fig. 3N4 was non-uniform. Although most sections of the fabric were adequately covered with powder, minor sections had less than optimal Si3N4 content. A qualitative water-drop hydrophilicity test was performed on these sections. It was noted that areas of heavy powder concentration exhibited improved hydrophilicity , followed by DTAB absorption  and oven drying . The fabric was then immersed in an aqueous AP4 slurry , wrung of excess slurry, oven dried , and cured between heated weighted plates . Washing and rinsing included sonication in DI water with 1 vol% Triton X-100 , followed by a sonicated DI water rinse , oven drying , and ~30 s compressed air blow-out (~ 690 kPa). The post-processing net mass gain for three representative samples, shown in Fig. 4-embedded spunbond PP layer are presented in Fig. 4 fibers were similar to the AP2 fabric for embedded mass, wetting, and non-wetting areas, dispersion, and adherence.A similar procedure was utilized for embedding the AP2 and AP4 fabric were prepared by cutting square (20 or 50 mm) sections, and selecting only areas that were evenly embedded with the Si3N4 powder. Multiple fabric sections were then assembled using ultrasonic welding to form individual multilayer swatches weighing about 0.36 ± 0.01 g in accordance with the sample mass of 0.40 ± 0.05 g specified by ISO 18184. All fabric specimens were then autoclaved inside 30 mL screwcap, polypropylene vial containers prior to antiviral experimentation. The treated test specimens (virus-containing supernatants) were analyzed for infectious virus titers immediately after inoculation, and after contacting the test specimens for the specified time points  in accordance with ISO 18184. Triplicate samples were used for all measurements.Antiviral test swatches of both the AP2), inner melt-blown layers (~ 50 g/m2), and a central spunbond layer embedded with AP4 Si3N4 powder (20 to 30 wt%) sandwiched between the other layers. The fabric layers were ultrasonically welded together. Testing was conducted by two certified laboratories—Nelson Laboratories  and Intertek Testing Services, Ltd . In addition, a modification of ISO 18562-3 was developed to detect ammonia (NH3) release from the Si3N4 powders. This protocol involved equilibrating 1 g of AP2 or AP4 powder within a closed 500 mL clamshell reactor for 30 min, then subsequently measuring NH3 concentrations within the chamber under either static (30 min) or flowing air  at ambient  or elevated  conditions. Released NH3 was measured using industrial 5–100 ppm colorimetric gas detection tubes .Four- or five-layer prototype masks and representative mask swatches were prepared for standard industrial mask tests including ASTM F2299 and EN 13274-7 for filtration efficiency, EN 14683 for differential pressure drop, and ISO 18562-2 for particle shedding. The prototype masks and swatches consisted of outer spunbond PP fabric layers .2 Si3N4 powder. Reductions of 64.9% and 99.8% occurred within one minute at concentrations of 7.5 and 15.0 wt%/vol. of Si3N4, (p = 0.29 and 0.07), respectively. Within five minutes, viral reductions were 98.5% and 99.8% (p = 0.08 and 0.07), respectively; and after thirty minutes, viral loads were reduced by 99.5% and 99.8% for the 7.5 and 15.0 wt%/vol. concentrations (p = 0.07 and 0.07), respectively. Vero E6 cell viability testing was conducted by exposing the mammalian cells to the Si3N4 powder in the virogenic medium, but without adding the virus. No cell death was observed at either Si3N4 concentration or at any of the incubation time points (data not shown). Mammalian cell viability was therefore deemed to be 100% in the presence of the dispersed Si3N4 powder.The first series of tests used the OC43 human β-CoV as a surrogate for SARS-CoV-2. The pathogenicity of the β-CoV is significantly lower than SARS-CoV-2 and therefore it could be reasonably handled in a BSL-2 laboratory. The results of these tests are graphically presented in Fig. 3N4 powder, the viral load was reduced by 91.4% and 99.3% (p =  < 0.01 and < 0.01), respectively. A five-minute exposure resulted in reductions of 97.8% and 99.99% for the two powder concentrations (p = 0.02 and 0.02), respectively; and at thirty minutes of exposure, reductions were 99.4% and 99.99% for 7.5 and 15 wt%/vol., (p = 0.12 and 0.12), respectively.After completing tests using the β-CoV, activities were moved into the BSL-3 laboratory for testing with SARS-CoV-2. Results of these experiments are provided in Fig. 3N4 as an antiviral compound, SARS-CoV-2 antiviral assessments were also conducted using solid Si3N4 and PEEK discs. Results of these tests are presented in Fig. 3N4, but virus inactivation on the solid discs was lower than that of the powders. Inactivation totals were 53.6%, 59.6%, 65.6%, 73.5% and 92.8% at 0, 5, 10, and 30 min and 24 h, , respectively. As noted, significant virus incubation time was required to achieve greater than a 2-log reduction. This was likely due to the reduced surface area of the discs in contact with the virogenic medium.As an additional analysis of the efficacy of Si3N4-embedded nonwoven fabric was prepared and assessed for its SARS-CoV-2 antiviral effectiveness. Two series of tests were conducted using AP2 and AP4 powder. Results are presented in Figs. 2 Si3N4-embedded fabric showed approximately 50% reduction in viral load after 5 min of incubation. Progressive inactivation of the virus at longer time points occurred with viral load reductions of 79%, 83% and ~ 87% at 10, 30, and 120 min, , respectively. Similar reductions were also noted for the AP4-embedded fabric, with inactivation rates of approximately 48%, 66%, 84%, and 92% at 5, 10, 30, and 120 min , respectively. Although a greater than 2-log reduction was observed at 120 min, the antiviral efficacy of the fabric samples was also lower compared to the powders. This observation is presumed to be due to the hydrophobic nature of the spunbond PP fibers which likely inhibited intimate contact between the embedded powder particles and the virogenic solution.Lastly, Si3N4 particle release from the mask fabric. Average values for PM2.5 and PM10 were identical at 1.25 ± 0.5 µg/m3, and both were well within permissible limits of 12 and 150 µg/m3, respectively. Breathability of the test masks was determined using EN 14683 which measures differential pressure though the fabric. The resulting drop in pressure was 53 ± 2 Pa/cm2. This value meets EU and US specifications for Type IIR medical masks for medium splash protection , but the outcome was slightly higher than the Type I requirement (< 40 Pa/cm2).An example of a prototype mask is shown in Fig. 3N4 is due to a hydrolytic surface reaction that converts the nitride to an oxide with the release of nitrogen [2 and AP4 Si3N4 powders at masses that were at least eight times the equivalent amount of powder embedded into an individual mask. Results for this test are provided in Table 3  for the AP2 Si3N4, but none in flowing air. The AP4 powder showed no detectable NH3 regardless of test condition. Various regulatory agencies have established limits on time-averaged occupational exposure to NH3. The American Conference of Governmental Industrial Hygienists (ACGIH) set an 8 h time-weighted exposure of 25 ppm and a 15 min short-term exposure (STEL) of 35 ppm. US OSHA has an 8 h permissible limit of 50 ppm, whereas NIOSH and California OSHA recommend a 10 h limit of 25 ppm and a 15 min STEL of 35 ppm (https://www.cdc.gov/niosh/pel88/7664-41.html). Although the methods for performing workplace tests differ from this mask test, it is clear that AP4 Si3N4 powder is within permissible exposure levels whereas the AP2 powder remains questionable. The reason the AP2 powder has higher NH3 emissions is likely due to the formation of an amorphous silicon-yttrium–aluminum oxynitride (SiYAlON) phase during the sintering and hot-isostatic pressing operations ; and while a limited number have performed third party antipathogenic testing, even fewer have conducted studies against SARS-CoV-2. Those that are reporting effectivity against the COVID-19 virus typically use metal or metal oxide nanoparticles. Most companies are startups with little or no experience in large-scale manufacturing and FDA or EPA regulatory requirements . As examRS-CoV-2 . Borkow R assays . Balagnacubation . Gopal ucubation . Marti, lization . Their c. employed PRISMA guidance [. evaluated 12 masks, of which six were either N95 respirators or surgical masks, while the remaining were consumer oriented. Embedded antimicrobial agents included citric acid, and/or nanoparticles of copper (Cu), copper iodide (CuI), zinc (Zn), silver (Ag) or their respective oxides . None of these masks were evaluated for their effectiveness against SARS-CoV-2 either, but all broadly claimed to be capable of eliminating virus, bacteria, and fungi [. identified 17 commercial antimicrobial masks by brand name. Agents in these masks included metal or metal-oxide nanoparticles , iodine, salts, organosilanes, or graphene. Detailed investigation of product websites revealed that only four had been cleared by the FDA as either N95 respirators or surgical masks, twelve were consumer masks, and one was not a mask at all, but an antimicrobial face spray. Four of the masks claimed to be effective against SARS-CoV-2, but test results were not provided. Blevens et al. also conducted a more recent review, but focused solely on consumer cloth masks that contained silver as the antimicrobial agent [. They obtained samples of nine silver or copper impregnated masks and subjected them to a DI water soak, saliva tests, and up to ten simulated household laundry cycles [The plethora of vendors who have jumped into the market has prompted the publication of several critical and systematic reviews on masks containing antimicrobial agents –53. For guidance  to selecguidance . Althougnd fungi . In a moal agent . They inal agent –60. Thisy cycles . They foIt is important to note that the FDA defines products that are intended for the “diagnosis of disease or other conditions or in the cure, mitigation, treatment, or prevention of disease” as medical devices. This includes antimicrobial masks. The FDA published (2004) and has subsequently revised (2020–2021) guidance for respirators, surgical, and commercial masks –51. All 3N4, the results showed that this unique material was effective in reducing viral loads. The data confirm that powders produced the greatest viral reductions  substantially met filtration, breathability and particle shedding standards. A modified chemical release protocol showed no detectable ammonia from at least one of the test Si3N4 powders. Lastly, although not evaluated in this study, Si3N4 is not expected to be an environmental hazard like most other antimicrobial agents. Si3N4 is composed of the two most abundant elements in the earth’s crust and atmosphere , respectively. In summary, although this study provides credible evidence of the efficacy of Si3N4-embedded fabric against a critical respiratory pathogen, the authors recognize that significant additional development, testing, and regulatory approvals will be necessary before effective PPE can be released to the medical community or the general population.In light of this information, the current study was undertaken as an initial foray into the development of a novel antipathogenic mask in advance of commercial considerations. The objective of the study was to perform a reasonable evaluation of a potential product in accordance with accepted industrial standards. The study methodically encompassed testing of powders, solids, and embedded nonwoven fabric against two human coronaviruses—the minimally pathogenic OC43 β-CoV  and the SARS-CoV-2 virus. Using all three forms of Si3N4 powders, solids, and embedded PP fabrics were tested for their antiviral efficacy against SARS-CoV-2 with viral load reductions of 99.99% at ≤ 5 min (powders), ~ 93% in 24 h (solids), and 87% ~ 92% in 120 min (embedded fabrics), respectively. For all three Si3N4 materials, virus inactivation was found to be concentration and time dependent . Prototype masks (or mask swatches) were also evaluated for filtration efficiency, differential pressure, particle shedding, and chemical release. Results of these standard mask tests were generally within prescribed safety limits. Given this initial study, Si3N4-embedded nonwoven fabric may represent an advancement in the fight against respiratory diseases. Its incorporation into facial masks may upgrade personal protective devices from simple “capture and retain” to effective “capture and kill” protection.SiMcEntire et al. McEntire et al. McEntire et al. McEntire et al. The following US and International pending patents are a partial result of this study:


Protein biosynthesis in mitochondria is tightly coupled with assembly of inner membrane complexes and therefore must be coordinated with cytosolic translation of the mRNAs corresponding to the subunits which are encoded in the nucleus. Molecular mechanisms underlying the regulation of mitochondrial translation remain unclear despite recent advances in structural biology. Until now, only one translational regulator of protein biosynthesis in mammalian mitochondria is known—protein TACO1, which regulates translation of COI mRNA. Here we describe the function of pentatricopeptide-containing protein PTCD2 as a translational regulator of another mitochondrially encoded subunit of cytochrome c oxidase—COIII in the HeLa cell line. Deletion of the PTCD2 gene leads to significant decrease in COIII translation efficiency and impairment in CIV activity. Additionally, we show that PTCD2 protein is partially co-sedimentates with associated mitochondrial ribosome and associates with mitochondrial ribosome proteins in pull-down assays. These data allow concluding that PTCD2 is a specific translational regulator of COIII which attracts the mRNA to the mitochondrial ribosome. In the course of billions of evolution years, the mitochondria dramatically reduced the genome of their ancestors: almost all protomitochondrial genes were transferred to the nucleus or lost . NowadayS. cerevisiae is governed by binding of specific translational activator to prolonged 5′-UTR and/or mitochondrial ribosome  methionine was added. After incubation at 37 °C for 45 min the medium was replaced with fully supplemented DMEM containing cold methionine and the cells were harvested. Samples were further analyzed by 18% SDS-PAGE and autoradiography. Signals were recorded on Storage Phosphor screens using a STORM 865 scanner . ImageJ software  was used for quantification.Mitochondrial translation products were labeled as described in . BrieflyWestern blot analyses were performed conventionally using following antibodies: anti-PTCD2 , anti-MRPS27 , anti-MRPL44 , anti-Cox4 , anti-COII , anti-COIII , anti-goat IgG HRP conjugated , ECL Anti-rabbit IgG HRP linked , according to manufacturers’ protocols. Blots were stained with SuperSignal West Pico ECL reagents  and visualized with ChemiDoc imaging system .2, 1.5 mM Tris-HCl, pH 7.5). Cells were homogenized by tight pestle in a Dounce homogenizer. After addition of 2.5xMS Buffer , cell debris was pelleted at 1300× g for 5 min at 4 °C. The mitochondria were pelleted by centrifugation at 18,000× g for 15 min at 4 °C. Mitochondria quantity was estimated by measurement of total mitochondria protein concentration by Bradford assay. Mitochondria pellets were stored at −80 °C until use.The isolation of human mitochondria was performed according to . Cells wg. Coomassie dye  was added to the supernatant to give a detergent/dye ratio of 8, and the samples were subjected to electrophoresis in a 4–14% gradient gel. After electrophoresis, either in-gel respiratory complex activities were measured, or Western blot analysis was performed. The measurement of complex I activity the gel was performed according to [BN-PAGE was performed as described in . Brieflyrding to . Gels we4 cells, which were frozen/thawed two or three times in isotonic medium before using. To measure the activity of cytochrome c oxidase, the decrease in absorbance at 550 nm was monitored for 3 min using Infinite M200Pro plate reader . The specificity of the activity of complex IV was checked by addition of 2 μL of 1M potassium cyanide (KCN). The resulting activity was calculated using formula “CIV activity (nmol cyt c/min/106 cells) = (ΔA(550 nm)/min)/(ε × cell number), where ε = extinction coefficient for reduced cytochrome c 18.5 mM−1cm−1.A reaction mixture containing 200 µL buffer , 10 µM reduced cytochrome c, and 2 µL dodecylmaltoside solution (20%) was added into a well of 96-well plate. The reaction was started by adding 2–10 × 107 cells were collected, washed with PBS and lysed in 1 mL of 10 mM HEPES pH 7.4, 120 mM KCl, 20 mM magnesium acetate, 5 mM β-mercaptoethanol, 1.7% Triton X-100 for 30 min on ice. After clarification at 25,000× g for 30 min, lysates were applied to 10–40% linear sucrose gradient prepared on the same buffer without detergent. After ultracentrifugation at 80,000× g for 18 h  gradients were fractionated with Gradient Station ip . Proteins in fractions were sedimentated with methanol/chloroform and applied to Western blotting.Approximately 10PTCD2 cDNA was amplified from total HeLa cDNA using 5′-ATCGAGGCCTCTGAGGCCATGGTCCGAGACAGTATGG-3′ and 5′-ATCGAGGCCTGACAGGCCTTAAAGATCTTCTTCGCTAATAAGTTTTTGTTCCTCAGCCAACAGGGACTGG. The fragment was cloned into pET30a vector (Novagen), and verified by Sanger sequencing. Resulting vector was transformed into BL21(DE3)/pLysS E. coli strain. 5 mL of LB medium supplemented with 50 ug/mL kanamycin and 20 ug/mL chloramphenicol were used as starting overnight culture grown at 37 °C with agitation; 1L of LB with appropriate antibiotics were inoculated with starting culture and incubated at 30 °C and agitation until OD600 reached 0.7–0.9. Expression was induced by adding IPTG up to 0.25 mM, cells were incubated for 4 h at 30 °C. Then cells were collected by centrifugation at 3000× g for 10 min, washed with PBS, resuspended in 40 mL of PBS, and lysed by sonication . Inclusion bodies were pelleted at 25,000× g for 20 min and dissolved in 7 mL of 25 mM Tris-HCl pH 7.5, 500 mM NaCl, 25 mM imidazole, 8M urea. After centrifugation , dissolved inclusion bodies were applied to 1 mL Ni-NTA column  connected to AKTA Purifier chromatography system  and pre-equilibrated with the same buffer. After extensive washing with the same buffer (40 column volumes), recombinant PTCD2 was eluted with the same buffer supplemented with 300 mM of imidazole. After elution fractions contained PTCD2 were combined and dialyzed against 4 changes of 25 mM sodium phosphate buffer pH 7.5, 150 mM NaCl for 24 h. Protein concentration was measured by Coomassie Protein Assay .g for 1 h at 4 °C. The supernatant was incubated first with 25 µg of recombinant 6xHis-tagged PTCD2 for 1 h at 4 °C with gentle agitation and then with Ni-NTA-Sepharose . After washing the resin, the proteins were eluted according to the manufacturer’s standard protocol. The eluted proteins were precipitated by methanol/chloroform and subjected to proteomic analysis.0.5 mg of HeLa mitochondria were resuspended in solubilizing buffer (50 mM imidazole-HCl (pH 7.0), 50 mM NaCl, 1 mM EDTA, 2 mM 6-aminohexanoic acid) supplemented with 2% dodecylmaltoside. After incubation for 40 min on ice, the insoluble material was removed by centrifugation at 18,000× 4HCO3). The pieces of gel were dried in acetonitrile, rehydrated in solution 2 (100 mM NH4HCO3 and 20 mM DTT) and incubated for 30 min at 56 °C. Next solution 2 was discarded and the samples were incubated in solution 3 (100 mM NH4HCO3 and 20 mM iodoacetamide) in the dark for 20 min, washed twice with water, three times with solution 1, dried in acetonitrile and trypsinized with Trypsin Gold  in 100 mM NH4HCO3 at 37 °C for 6 h. Peptides were desalted using Pierce C18 Tips, 100 ul according to manufacturer’s instructions. Peptides eluted from the tips were dried on vacuum manifold and solubilized in 0.1% formic acid.Proteome analysis was performed as described in  with min® PepMap™ RSLC inner diameter of 75 μm, Thermo Fisher Scientific, Rockwell, IL, USA). The peptides were eluted with a gradient of buffer B  at a flow rate of 0.3 μL/min. Total run time was 90 min, which included initial 4 min of column equilibration to buffer A (0.1% formic acid), then gradient from 5 to 35% of buffer B over 65 min, then 6 min to reach 99% of buffer B, flushing 10 min with 99% of buffer B and 5 min re-equilibration to buffer A.One microgram of peptides in a volume of 1–4 uL was loaded onto the Acclaim μ-Precolumn  at a flow rate of 10 uL/min for 4 min in an isocratic mode of Mobile Phase C . Then the peptides were separated with high-performance liquid chromatography  in a 15 cm long C18 column  in the range from 100 m/z to m/z value determined by a charge state of the precursor, but no >2000 m/z. The maximum integration time was 50 and 110 ms for precursor and fragment ions, correspondently. AGC target for precursor and fragment ions were set to 1 × 106 and 2 × 105, respectively. An isolation intensity threshold of 50,000 counts was determined for precursor’s selection and up to top 20 precursors were chosen for fragmentation with high-energy collisional dissociation (HCD) at 29 NCE. Precursors with a charge state of +1 and more than +5 were rejected and all measured precursors were dynamically excluded from triggering of a subsequent MS/MS for 20 s.MS analysis was performed at least in triplicate with a Q Exactive HF-X mass spectrometer . The temperature of capillary was 240 °C and the voltage at the emitter was 2.1 kV. Mass spectra were acquired at a resolution of 120,000 (MS) in a range of 300−1500 The obtained raw data were processed using the MaxQuant software  with the


The ZnCoO@NF electrode exhibited a superior specific capacitance of 1132 F·g−1 at 2 A·g−1 and revealed 99% cycling stability after 7000 cycles at a high current density of 20 A·g−1. The improved performance of the ZnCoO@NF electrode is attributed to the highly stable structure of the micro/nano-multiscale architecture, which provides both the high conduction of electrons and fast ionic transportation paths simultaneously.Scientific research is being compelled to develop highly efficient and cost-effective energy-storing devices such as supercapacitors (SCs). The practical use of SC devices is hindered by their low energy density and poor rate capability due to the binding agents in fabricating electrodes. Herein, we proposed flower-like highly open-structured binder-free ZnCo Super2O4, FeCo2O4, CuCo2O4, NiCo2O4, and MnCo2O4 can significantly increase the performance of PCs [2O4 is the most promising candidate due to the low toxicity of zinc metal and reasonably significant capacitance of Co3O4 (3560 F·g−1), and it also possesses good stability at low cost [2O4 electrode’s overall performance, three general strategies are typically employed: (i) development of nanostructured materials with a visually appealing structure and a large surface area; (ii) research and development of new composites with high conductivity, which includes carbon nanotubes and graphene; and (iii) enhancement of the SC device’s potential window, as energy density is inversely proportional to the potential window’s square (E = 1/2CV2) [Cobalt-based binary metal-oxide electrode materials such as ZnCoe of PCs ,12,13. Ilow cost . However 1/2CV2) . Increas 1/2CV2) . Binders 1/2CV2) . Binder- 1/2CV2) .2O4, showing a suitable specific capacitance of 92 mF·cm−2 at 0.5 mA·cm−2 [2O4 electrode with a good capacitance of 689.4 F·g−1 at 1 A·g−1 with excellent cyclic stability of 97.1% after 1500 cycles [2O4 to make binder-free electrodes and obtained a good capacitance of 127.8 F·g−1 at 1 mA·cm−2 with excellent cycling stability of 3000 cycles [2O4 have been ongoing, the cycling stability and rate performance are still crucial and need to be significantly improved. The electrochemical performance of ZnCo2O4 electrodes can be further improved by exploring the various morphologies. We propose that electrodes of ZnCo2O4 with micro/nano morphology can increase surface area and pore size, resulting in increased energy density and rate performance.Saravanakumar et al. fabricated a binder-free hierarchical electrode of ZnCo mA·cm−2 . Fu et a0 cycles . Kamble 0 cycles . Althoug2O4 micro-flowers composed of nanosheets supported on (ZnCoO@NF), improving the rate capability up to 91.8% when current varied from 2 to 20 A·g−1. The ZnCoO@NF electrode exhibits a superior capacitance of 1132 F·g−1 at 2 A·g−1 with excellent cycling stability of ~99% after 7000 cycles at a high current density of 20 A·g−1. The improved performance of the ZnCoO@NF electrode is attributed to the highly stable structure of micro/nano-architecture, which provides both high electronic conduction and fast ionic transportation paths.Herein, we proposed binder-free ZnCo3)2·6H2O, 4 mmol of Co(NO3)2·6H2O, 2 mmol of NH4F, and 6 mmol urea in 40 mL of deionized water and ultra-sonicating the solution for 60 min. Afterwards, a hygienic piece of nickel foam (NF) was hung on the inside walls of a Teflon autoclave, and the solution mixture was injected into the Teflon autoclave. After securing the autoclave, it was placed in an electric oven and heated to 135 °C for 16 h. The NF was assembled with ZnCoO-oxide precursors, washed with deionized water and ethanol, and sonicated for 5 min to remove the remaining particles from the surface of NF. For further processing, the ZnCoO@NF was dehydrated in an air furnace for 12 h. To improve the crystallinity, the ZnCoO@NF precursor was heated for 2 h at 250 °C in the air atmosphere. The experiment was repeated twice and yielded the same results each time.The 2D ZnCo-oxide micro-flowers assembled by nanosheets on nickel foam (NF) were grown directly using a low-cost and straightforward hydrothermal synthesis method. In a usual cycle, a homogenous solution was made by mixing 2 mmol of Zn and transmission electron microscopy  were both used to examine the materials’ microstructures and morphology. X-ray powder diffraction (XRD)  was used to determine the crystal structure of the synthesized product. The X-ray source was an Escalab (250Xi)  with an Al Ka (1486.5 eV). The specific surface area calculation was made with a Quantachrome Instrument  and the Brunauer-Emmett-Teller (BET) method.s (F·g−1) represents the specific capacitances, I represents the current (A), Δtd (s) represents the discharging time, m (g) represents the active mass of the ZnCoO material on NF, and the potential window is represented by ΔV (V).The electrochemical tests, including cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS), were performed in an open-circuit position in a frequency ranging from 0.001 Hz to 100 kHz. All these tests were performed using a platinum sheet (counter electrode), Ag/AgCl (reference electrode), and ZnCoO@NF (working electrode) in a 6 KOH electrolyte at room temperature using an electrochemical workstation  in a three-electrode configuration. The specific capacitance (Cs) was calculated using the following Equation (1):−1.2O4 (PDF# 23-1390). These findings are also in line with the results of the SEM. It should be noted that in the SEM and TEM images, we can see some residual nanoparticles. It is confirmed that there is no effect from these residual nanoparticles on the electrochemical performance of the electrode.TEM analysis was further conducted to investigate the ZnCoO structure and surface morphologies in more depth. A characteristic TEM image with low resolution represents nanosheets of ZnCoO a,b. Figu3/g at 1.0 P/P0, which means that ZnCoO@NF has a highly porous structure (55 m2·g−1). Moreover, this study demonstrated an H1-type hysteresis loop, which suggested the presence of a mesoporous structure in the solution. The PSD was calculated from the desorption isotherm using the Barrett-Joyner-Halenda (BJH) method, as shown in 2O4 (JCPDF# 23-1390). The particular diffraction peaks of ZnC2O4 located at 21°, 32°, 37°, 39°, 44.7°, 56°, 59.5°, and 66° correspond, respectively, to 111, 220, 311, 222, 422, 511, and 440 lattice planes. Compared with the standard ZnCo2O4 spinel, these results are consistent with the previous findings [3O4 was added as a comparison to confirm the difference between ZnCo2O4 and Co3O4. The diffraction peaks of as-prepared ZnCoO@NF clearly matched with JCPDF# 23-1390 and confirm the pure phase of ZnCo2O4. The crystal structure ZnCo2O4 nanostructures are shown in 4 with Co2+ at the tetrahedral sites (8a) in the spinel Co3O4 replaced by Zn2+ offers a better stability. In addition, the spinal structure can help increase the redox reaction sites, which boosts the specific capacitance of bimetallic oxide-based electrodes. Thus, choosing the bimetallic oxide and crystal structure is critical for overall performance and structural stability during the electrochemical discharge process [The XRD pattern of ZnCoO@NF a is well−1 assigned to the characteristic F2g, Eg, F2g, and F2g phonon modes, respectively. The presence of Zn, Co, and O in these distinct peaks of the Raman spectrograms suggests the formation of ZnCo2O4. This indicates that the prepared sample is free of contaminants [The Raman spectrum further characterized the as-synthesized ZnCoO@NF to confirm the Raman band characteristics. From aminants .3+/Co2+ during the charge/discharge process [The electrochemical performance results of ZnCoO@NF are shown in  process . The red process . Moreove process .−1) (b). The GCD curves are nearly symmetric (Coulombic efficiency 98%), have apparent redox behavior, and agree well with the CV results, demonstrating the pseudocapacitive charge storage features. The charge and discharge curves primarily have voltage terraces at about 0.3 V and 0.36 V, respectively. Equation (1) can be used to calculate the specific capacitance Cs based on the curves. Based on Equation (1), the obtained specific capacitances of the ZnCoO@NF electrode are about 1132, 1120, 1100, 1060, and 1040 F·g−1 at current densities of 2, 3, 5, 10, and 20 A·g−1, respectively, as shown in −1, the capacitance remains at 91.8%. The capacitance of the ZnCoO@NF electrode is much better than other electrodes such as Gd-doped CeOx nanoflowers (280 F·g−1 in 1 M NaOH at 1 V·s−1) [3O4 nanosheets on carbon foam (106 F·g−1 in 1 M NaOH) at a scan rate of 0.1 V·s−1 [The electrochemical property of the ZnCoO@NF electrode was tested based on charging and discharging at various current densities to accurately estimate the charge storage capability. The GCD measurements of the ZnCoO@NF electrode were carried out in a potential window ranging from 0.0 to 0.45 V. 1 V·s−1)  and meso.1 V·s−1 .2O4-based electrode materials.Because of its multi-channel porous nature and enhanced ionic transportation, the ZnCoO@NF demonstrated exceptional specific capacitance, far exceeding that of previously reported ZnCoThe total capacitance of ZnCoO@NF can be attributed to the following significant contributions: (1) the micro-flowers composed of nanosheets with highly open structures supply abundant active sites for the Faraday reaction and offers easy diffusion paths for fast ionic transportation; (2) the electrochemical performance can be promoted by improving the specific area, pore size, and multi-channel nano/micro-architecture.ct = 1.52 Ω), which means that ion diffusion and electrolyte penetration in the active materials are reduced. The solution resistance (Rs = 0.13 Ω) is the combination of the electrolyte’s and electrode’s internal resistance. The values of Rct and Rs are smaller than in pristine Co3O4 (Rs = 1.32 Ω) [s = 2.82 Ω and (Rct = 2.25 Ω) [s, Rct, C (the double layer capacitance), and W (the Warburg diffusion element). Hence, the ZnCoO@NF electrode possesses more capacitive-type charge-storage features [Furthermore, electrochemical impedance spectroscopy (EIS) was conducted to study the kinetics of charge transfer in the ZnCoO@NF electrode to confirm the charge transport properties.  1.32 Ω)  and ZnO  2.25 Ω) . The higfeatures .−1, and the results are shown in −1, the first and last five GCD cycles are shown in Another vital parameter to consider when evaluating the practical applications of SCs is their cycling stability. Thus, the cycling stability test of the ZnCoO@NF electrode was performed by deliberately running it for 7000 charge/discharge cycles at a high current density of 20 A·g−1 at 2 A·g−1 and 1040 F·g−1 at 20 A·g−1 with improved rate capability up to 91.8% when the current increased from 2 to 20 A·g−1. The ZnCoO@NF electrode shows excellent cycling stability of ~99% after 7000 cycles at a high current density of 20 A·g−1. Future energy storage devices will benefit from the new binder-less electrode material with high specific capacitance and rate capability. In light of the promising results, SCs combined with other energy conversion/storage devices may be commercially available soon.The ZnCoO@NF was successfully synthesized using a straightforward hydrothermal method followed by a thermal procedure. The ZnCoO@NF electrode exhibits excellent electrochemical properties in an aqueous KOH electrolyte. The ZnCoO@NF electrode demonstrates a high specific capacitance of 1132 F·g


The reactions employed molar H : BaTiO3 ratios of 1.2, 3, and 10 and variable temperatures up to 700 °C. The air-stable reduced products were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy, thermogravimetric analysis (TGA), X-ray fluorescence (XRF), and 1H magic-angle spinning (MAS) NMR spectroscopy. Effective reduction, as indicated by the formation of dark blue to black colored, cubic-phased, products was observed at temperatures as low as 300 °C. The product obtained at 300 °C corresponded to oxyhydride BaTiO∼2.9H∼0.1, whereas reduction at higher temperatures resulted in simultaneous O defect formation, BaTiOx2.9−H0.1□x, and eventually – at temperatures above 450 °C – to samples void of hydridic H. Concomitantly, the particles of samples reduced at high temperatures (500–600 °C) display substantial surface alteration, which is interpreted as the formation of a TiOx(OH)y shell, and sintering. Diffuse reflectance UV-VIS spectroscopy shows broad absorption in the VIS-NIR region, which is indicative of the presence of n-type free charge carriers. The size of the intrinsic band gap (∼3.2 eV) appears only slightly altered. Mott–Schottky measurements confirm the n-type conductivity and reveal shifts of the conduction band edge in the LiH reduced samples. Thus LiH appears as a versatile reagent to produce various distinct forms of reduced BaTiO3 with tailored electronic properties.We investigated the hydride reduction of tetragonal BaTiO 3, which include oxyhydride BaTiO2.9H0.1 and O-deficient BaTiOx2.9−H0.1□x, were obtained from reactions with LiH at various temperatures.Different forms of reduced BaTiO Reaction conditions can be varied by the choice of reducing agent , reaction temperature and time, and the activity/concentration of H−. The active reducing species may be H− or H2, or a combination.8,9 Typically, in the hydride reduction of transition metal oxides, the reduction is accompanied with O removal (i.e. O vacancy formation), and frequently there is a strict topotactic relationship between the original oxide and its reduced form.10,11 Actually, only in rare cases transition metal reduction and hydride ion insertion occur simultaneously, leading to oxyhydrides.12Hydride reduction of BaTiO3 reduction? We recently showed that the reduction of BaTiO3 can be achieved with a larger range of metal hydrides.13 In contrast to previous studies we found that hydride reduction leads to phases BaTiOx3−Hy□x−y) hydridic H is absent in reduced samples and particles show substantial surface alteration, which is interpreted as the formation of a TiOx(OH)y shell. Thus LiH appears as a versatile reagent to produce various distinct forms of reduced BaTiO3.An important question is what factors govern oxyhydride formation as opposed to exclusive vacancy formation during hydride reduction. What mechanism could apply for BaTiO22.13  and LiH powder . Prior to use, BaTiO3 was dried overnight in an oven at 200 °C. All steps of sample preparation for the synthesis reactions were performed in an Ar filled glove box. For a typical synthesis ∼0.5 g (2.1 mmol) of BaTiO3 was intimately mixed with LiH by grinding the materials together in an agate mortar for 20 min. We considered the molar proportions BaTiO3 + nLiH, with n = 1.2, 3, and 10. The BaTiO3/LiH mixture was subsequently pressed into a pellet with a diameter 9 mm. The pellet was then sealed inside a stainless steel ampule (with dimensions 10 mm ID and 50 mm length), which – after removal from the glove box – was placed in a box furnace. A K-type thermocouple was inserted and located in close proximity to the metal ampule. Ampules were heated for typically 48 h. Reaction temperatures varied from 250 to 700 °C. After cooling to room temperature, ampules were opened and the products washed with 0.1 M acetic acid (HAc) solution to remove excess LiH and metal oxide/hydroxide formed during hydride reduction. For washing, the pellets were crushed and sonicated with 50 mL HAc and then centrifuged. The procedure was repeated 3 times. As a last step, products were treated with 20 mL 95% ethanol and then dried at 120 °C under dynamic vacuum (<10−5 bar). The dried products corresponded to dark blue powders.As starting materials we used BaTiO2.2θ–2θ diffraction geometry. Powder samples were mounted on a Si wafer zero-background holder and diffraction patterns measured in a 2θ range of 20°–120° with 0.016° step size. The contribution of Kα2 radiation to the PXRD patterns was removed using the Panalytical X'Pert HighScore Plus software. The Rietveld method as implemented in the FullProf program was used for structure and phase analysis.14 A six-coefficient polynomial function was applied for the background. The peak shape was described by a pseudo-Voigt function. Patterns with pronounced peak shape asymmetries were refined as mixtures of two cubic phases. Site occupancies for the O atoms could not be refined reliably and were constrained to 1.PXRD patterns were collected on a Panalytical X'Pert PRO diffractometer operated with Cu Kα radiation and in 2.33 starting material.SEM investigations were carried out using a JEOL JSM-7000F machine equipped with a Schottky-type field emission gun and energy and wavelength dispersive detectors from Oxford instruments. Images were recorded in backscattering mode with an accelerating voltage of 15 kV. Samples for imaging were prepared by first producing a homogeneous suspension of particles in ethanol by sonication. Then droplets of the suspension were applied onto surface-polished aluminum pin stubs and left to dry. Energy-dispersion X-ray (EDS) and wave-dispersion X-ray (WDX) data were collected with an accelerating voltage of 8 kV and processed with the INCA software. Samples for EDS and WDX analysis were prepared by spreading sample powders on copper grids. Measurements were carried out by focusing the electron beam on selected individual particles and then collect statistical results. Quantification optimization was done with respect to BaTiO2.43 and TiO2 with known ratio).XRF was performed on a PANalytical Epsilon3 spectrometer, with working condition of 20 kV, high-resolution detector SSD, medium of air and filter of Al-200. Powder samples were pressed into pellets with diameter of 8 mm. Quantification results were calculated by comparing to reference standards (mixtures of BaTiO2.5−1. A dry air gas flow of 20 mL min−1 was applied.TGA experiments were carried out using a TA instruments Discovery system. The samples (∼15 mg powders) were heated in a platinum crucible from room temperature to 900 °C with a heating rate of 5 °C min2.6UV-VIS diffuse reflectance measurements were performed at room temperature on finely ground samples with particle size < 300 nm. Spectra were recorded in the range from 200 to 800 nm with an Agilent Cary 5000 UV-VIS-NIR spectrometer equipped with a diffuse reflectance accessory from Harrick. A polytetrafluoroethylene (PTFE) pellet (100% reflectance) was used as the reference.2.71H and 7Li MAS NMR experiments were performed at a magnetic field of 14.1 T  and MAS frequency of 60 kHz on a Bruker Avance-III spectrometer equipped with a 1.3 mm MAS HX probe. Proton spectra were acquired using a rotor-synchronized, double-adiabatic spin-echo sequence with a 90° excitation pulse of 1.2 μs followed by a pair of 50 μs tanh/tan short high-power adiabatic pulses (SHAPs) with 5 MHz frequency sweep.15–17 All pulses were applied at a nutation frequency of 208 kHz. 4096 signal transients with a 5 s recycle delay were accumulated for each sample. Shifts were referenced with respect to tetramethylsilane (TMS) at 0 ppm. 7Li spectra were collected using single-pulse (“Bloch decay”) protocol with 90° excitation pulse of 1.40 μs (179 kHz nutation frequency), 60 s recycle delay, and 64 signal transients per sample. Shifts were referenced with respect to solid LiF at 0 ppm. The amount of Li in each sample was estimated by relating its integrated 7Li NMR signal intensity to that of LiF in the same rotor volume, assuming molecular mass and density of 233.192 g mol−1 and 6.02 g cm−3 for BaTiO3 and 25.939 g mol−1 and 2.64 g cm−3 for LiF, respectively.The 2.8via electrophoretic deposition (EPD) process. Briefly, a homogeneous suspension was prepared by mixing 30 mg powder samples and 10 mg iodine in 30 mL of acetone via sonication. Two pre-cleaned FTO slides were immersed in the above suspension with 1 cm distance, and a DC potential of 30 V was applied between them for 3 min. After EPD process, the FTO slides with thin film were washed with water and dried naturally. 0.1 M NaOH (pH 13), in which oxyhydrides are stable,1 was used as electrolyte to perform Mott–Schottky measurements. The measurements were conducted in the conventional three-electrode system where a platinum wire, a 1 M Ag/AgCl electrode and the thin film on FTO served as counter, reference electrode and working electrode, respectively. The potentials were recorded versus 1 M Ag/AgCl and converted versus reversible hydrogen electrode (RHE) according to ERHE (V) = EAg/AgCl + (0.059 × pH) + EθAg/AgCl. The measurements were carried out by using the Gamry INTERFACE 1010T Potentiostat/Galvanostat/ZRA workstation in a dark setting at ac amplitude of 5 mV and a frequency of 10 Hz.Powder samples were assembled into particle-base thin film electrodes on fluorine-doped tin oxide (FTO) glass substrate 33.1The evolution of products with increasing temperature, from 250 to 700 °C, during 2 day experiments is displayed in 3, was specified by the manufacturer as 0.5 micron. This is confirmed in 3 particles is not recognizable anymore. 1.2H-600 particles seem smaller, rounded, and especially largely sintered. 1.2H-700 consists of micron-long needles – which are attributed to crystalline component – and irregular fused particles, which are attributed to amorphous component  and very similar to that of pristine starting material (which shows a continuous weight loss amounting to 0.15% up to 700 °C).13 For 1.2H-450 the initial weight loss is increased to 0.45% and for 1.2H-500 it is substantial, 0.9% at 350 °C. Obviously, compared with reduction at lower temperatures, the concentration of surface hydroxyl/water is largely increased for 1.2H-450, and especially for 1.2H-500. The initial weight loss seen in TGA most likely correlates with the surface alteration of 1.2H-450 and 1.2H-500 particles seen in SEM. This suggests that LiH reduction at temperatures higher than 400 °C increasingly affects and modifies the surface of BaTiO3 particles, which, after washing, results in a higher concentration of hydroxyl and adsorbed water.x values according to 3 (x = 0.5–0.6).1,2 The behavior of 1.2H-600 is then radically different. Its TG trace shows a large, ∼3%, weight loss up to 400 °C, then some small weight gain (0.5%), and finally further weight-loss above ∼650 °C up to about 800 °C. The product after the TG/air treatment (i.e. after heating and cooling to 900 °C) is white and corresponds to tetragonal BaTiO3 for the samples 1.2H-300 to 1.2H-450  behavior of metal hydride reduced BaTiO3 because of their significant initial TGA weight loss (>0.3 wt%). This can only be explained by water loss and signals significant surface alteration of reduced BaTiO3 particles. Next, we address in more detail the composition of the LiH reduced samples, in particular H-incorporation vs. O deficiency, and the possibility of Li incorporation.To summarize: LiH reduces BaTiO3.21H MAS NMR earlier for the analysis of metal hydride reduced BaTiO3 samples.131H MAS NMR is especially useful for unambiguously determining the hydridic H content, which then allows the deduction of O defect concentrations from TGA measurements. Importantly, protic H from (surface) hydroxyl and hydridic H as part of the bulk structure can be discriminated as positive and negative chemical shift contributions, respectively, in the spectra.13We have used 1H NMR spectra for the 1.2H-300, -350, -400, -450, 500, and -600 samples. Hydric H expresses itself as a single broad resonance peak at negative chemical shift whereas protic resonances at ∼1 ppm and in the region 6–7 ppm are attributed to surface OH species and secondary water.13 The increase of the protic H concentration, in particular the ones from surface OH, with increasing synthesis temperature of samples is highlighted in i.e. 0.2%–0.9%–3.3%, cf.1H NMR signal of the BaTiO3 starting material to that of adamantane (C10H16) in the same rotor volume and under identical experimental conditions.13 When applying the same procedure for the LiH reduced samples, we find XH = 0.09 (1) for all samples. This result is included in X□, see 2.9H0.1), whereas the 1.2H-350, -400 and -450 samples show an increasing O defect concentration (while keeping the H content constant). 1.2H-500 is void of hydridic H and one would assume that this sample corresponds to O-deficient BaTiO2.6. At the same time we remember that, starting off 1.2H-450, LiH reduced samples show surface alteration which then culminates in particle sintering for 1.2H-600.With the knowledge of the hydridic H concentration, the corresponding weight increase according to 7Li MAS NMR experiments. The spectra from the 1.2H-500 and -600 samples show that 1.2H-500 does not contain Li whereas a 7Li resonance is present in the spectrum of 1.2H-600, indicating some Li incorporation   the metal composition of particles is changed.To analyze the compositional integrity of the 1.2 M LiH reduced samples we performed x(OH)y. This is in agreement with the increasingly higher concentration of surface hydroxyl observed with increasing synthesis temperature. The 1.2H-500 sample would then correspond to “core–shell” particles with a BaTiOx3− core and a TiOx(OH)y shell/surface . The presence of a TiOx(OH)y shell/surface could then also explain the occurrence of sintering as fusion of reduced BaTiO3 particles via condensation reactions of Ti coordinated surface hydroxyl. As shown by NMR, Li is incorporated in the 1.2H-600 sample. We believe that Li is part of Li–Ti–O phases and concentrated in the interface of fused particles. The Ba/Ti ratio for 1.2H-600 according to XRF is just 0.6, which would correspond to a BaTiO3(core)/TiO2(shell) ratio of 1.5 : 1. It is then surprising that 1.2H-600 maintains an average cubic perovskite structure and that the large volume fraction of compositionally different surface appears virtually invisible in the PXRD pattern (cf.x(OH)y surface, similar to the surface disorder that was recently reported for tetragonal BaTiO3 nanocrystals.205O11 – in agreement with a Ba deficient sample – however, the fraction appears very small .13 The observed negative shift for the hydridic 1H has been attributed to the contact hyperfine interaction between the 3d electrons of Ti(iii) and the 1H nucleus. This shift mechanism is operative in both metallic systems and in paramagnetic insulators.21 For metallic BaTiOx3Hx it has been suggested that the electrons are delocalized in a conduction band,22 as opposed to a localized polaron scenario, and the hyperfine interaction results in a Knight shift that depends on the density of states at the Fermi level.23 The magnitude of the Knight shift is known to increase with the concentration of charge carriers.24 Thus one would expect that the charge carrier concentration in our samples increases with increasing Knight shift, that is, from 1.2H-300 to 1.2H-450.We now return to the 3.3etc is provided as ESI .†We also performed hydride reduction experiments with a larger LiH concentration, 3 M LiH and 10 M LiH . 1H NMR analysis revealed then slight but decisive differences. cf.X = 0.09 (1) for all samples. And analogous to the 1.2 M LiH reductions, the spectra for 3H-500 and 10H-500 do not exhibit a resonance in the negative ppm region, indicating the absence of hydridic H.At first sight, the products of 3H and 10H reductions at 350 and 500 °C appear similar to the corresponding 1.2H experiment. 3 depends strongly on the reducing agent  and that reduced BaTiO3 samples frequently represent complex, heterogeneous, materials, due to the simultaneous presence of vacancies and H in the anion substructure.13 With LiH it appears that a single reducing agent can produce in a controlled way different stages of reduced BaTiO3, depending on reaction temperature (cf.x3−Hy□x−y) polymorph.27 However, experimentally it appears to be difficult to assign the nature of the band gap and frequently a direct band gap is also assumed for the tetragonal form. BaTiO3 has attracted attention as photocatalyst and there have been numerous investigations into its electronic properties.28,29 For becoming useful photocatalysts nearly all wide gap semiconductors  require chemical modifications to generate donor/acceptor levels in the band gap, or noble metals to facilitate charge transfer and separation. Frequently, partial reduction can be used to improve photocatalytic and/or photo-electrochemical activity by “self-doping”. The most prominent example is the conversion of TiO2 to black TiO2, which has a blue color due to the absorption in visible and near-IR region.30,31 This is similar to hydride reduced BaTiO3 for which, however, electronic and photocatalytic properties are far less investigated. Originally BaTiOx3−Hx, with x = 0.3 and 0.6 (as obtained from CaH2 reduction) has been attributed a high electronic conductivity.1 Later thin films of BaTiOx3−Hx were found to be semiconducting for x < 0.2 and metallic for 0.2 < x < 0.6.3BaTiO32 It implies that states at the bottom of the conduction band are occupied (i.e. a n-doped semiconductor) and proves the earlier made conjecture that electrons form delocalized bandstates in reduced BaTiO3. In contrast,  polaron states would yield shallow traps below the conduction band, and their interband transitions would express themselves as exponential onset of absorption just below the fundamental absorption edge.33 Interestingly, a recent report on self-doped TiO2 showed that – depending on conditions – this material can be obtained either in the polaron or the bandstate form.34 We note that black BaTiO3 obtained from Al-reduction displays a very similar UV-VIS spectrum as e.g. 1.2H-350.35UV-VIS diffuse reflectance spectra are shown in 1H MAS NMR spectra when correlating the charge carrier concentration with the Knight shift. The free carrier contributions complicate the estimate of the band gap. Tauc plots – which were not corrected for interband transitions – suggest a band gap of 3.18 eV for BaTiO3 and 1.2H-250, and an upward shift to 3.25 eV for 1.2H-300 and 1.2H-350 and to 3.4 eV for 1.2H-450. However, we conjecture that the band gap within these oxyhydride materials is only slightly changed – if at all. The K–M transformed spectra for 1.2H-500 and 1.2H-600 suggest then a significant shift of the absorption edge for the materials void of hydridic H. However, Tauc plot evaluation would not give a reliable determination of the band gap  exhibits a flat band potential at −0.36 V vs. RHE, which is a significant positive shift with respect to the pristine BaTiO3. For 1.2H-450 and 1.2H-500, corresponding to O-deficient BaTiO2.6H0.1□0.3 and BaTiOx3− core/TiOx(OH)y shell material, respectively, the conduction band edge is shifted back to app. −0.5 V vs. RHE. Curiously, the slopes remain approximately at the same level for all samples, although the UV-VIS and 1H MAS NMR investigations strongly suggest that the reduced samples are metallic and possess different charge carrier concentrations. The slope of a Mott–Schottky plot is inversely proportional to the charge carrier concentration and the dielectric constant. Thus, one may infer that the dielectric constant of the reduced cubic samples is drastically diminished compared to ferroelectric tetragonal BaTiO3  display substantial surface alteration, which is interpreted as the formation of a TiOx(OH)y shell. Thus LiH appears as a versatile reagent to produce distinct forms of reduced, metallic BaTiO3.Hydride reduction has developed into a versatile method for modifying transition metal oxides, yielding O-deficient or mixed anion oxyhydride phases.There are no conflicts to declare.RA-010-D0RA07276A-s001


The study showed the stability of obtained layered TiO2-anatase close to 1200 °C. This research confirmed for the first time that the transition of mesocrystalline anatase to the rutile phase occurs between 1000 °C and 1200 °C, which is more than 400 °C higher than the transition of bulk TiO2 due to the used precursor. A small quantity of K-phase nanowhiskers, which issued after 800 °C in the composite based on TiO2, stimulated a fourfold increase in photocatalytic performance. This study offers a new approach to the construction and preparation of effective nanocrystalline photocatalyst.An array of highly oriented anatase nanoparticles was successfully prepared from NH Hence, the manipulation of phase stability and formation are essential for both researchers and industrial organizations. At room temperature and atmospheric pressure, the thermodynamically stable modification of TiO2 is rutile. Anatase and brookite can be kinetically stabilized. Single-crystal anatase irreversibly transforms into rutile at close to 600 °C in air; however, data are also available on transition temperatures in the range of 400–1200 °C due to differences in methods for determining transition temperatures, the presence of impurities, and variations in crystallite sizes. Thus, anatase mesocrystals are described in  direction [In addition, TiOearchers  developeirection .2-based materials continues unabated, partly due to the search for affordable environmental cleanup materials. Furthermore, the thermal stability of anatase mesocrystals has not been yet reported.An analysis of the literature has shown that by now there are a significant number of experimental works devoted to the study of the photocatalytic properties of titanium dioxide, including the methods of its synthesis in the form of mesocrystals. Despite the amount of data available, interest in TiO2 composite.In this study, preparation of photoactive oriented nanomaterials based on titanium dioxide and nonionic polymer was explored. Herein, we have presented a strategy to improve photocatalytic response of TiOThe temperature limit of stability of an array of highly oriented anatase nanoparticles was confirmed, and the temperature of phase transition of titanium dioxide mesocrystals from anatase to rutile was determined for the first time.4)2TiF6, H3BO3 and PEG 400 were obtained from Sigma-Aldrich . All chemicals were used without further purification.2TiF6 (0.594 g) and H3BO3 (0.372 g) in the stoichiometric molar ratio 1:2 were mixed well with distilled water (30 mL) under stirring to form solution. After this, the PEG400 (9 g) solution was slowly added to prepared mixture under constant stirring. The viscous solution was kept at 35 °C for 20 h. The final products were collected by centrifugation at 7000 rpm for 7 min and then washed using H2O and acetone for three cycles. After drying at air sample NH4TiOF3 was obtained.First, NHObtained precursor (powder) were calcined in a muffle at certain temperatures  for 2 h at air atmosphere.−1 at air and argon. MS gas analysis was conducted at all temperature ranges. BET low-temperature nitrogen adsorption measurements were performed using an ATX-6 analyzer . Measurements of photocatalytic activity were conducted under irradiation of a suspension of the analyte MC (1.5 mg MC in 2 mL H2O) in 40 µL aqueous solution of crystal violet (1 mM) in a quartz cuvette with an Ocean Optics HPX-2000  deuterium—halogen lamp  in a cell thermostated at 37 °C. Spectrophotometric analysis was performed using an Ocean Optics QE65000 spectrometer . All samples were kept in the dark for 45 min prior to conducting the degradation study. The chemical analysis was performed by X-ray photoelectron spectroscopy (XPS) using a SPECS spectrometer  with Mg Kα excitation (1253.6 eV).The phase analysis was determined via X-ray diffraction (XRD) using a Bruker D8 Advance X-ray Diffractometer . The morphology of the samples at all synthetic stages were recorded on scanning electron microscope Carl Zeiss NVision 40  equipped with an INCA analyzer Oxford Instruments X-Max . Raman spectroscopy was conducted using a Renishaw inVia Reflex spectrometer  with an illumination wavelength of 633 nm. Thermogravimetric and thermocalorimetric analysis was carried out using a Simultaneous Thermo Analysis Netzsch STA 409 PC Luxx . Heating was conducted from room temperature to 1200 °C with a heating rate increase of 5 °C min3 mounted on glass fiber . Dataset combined two subsets of 1440 images collected with 0.25 deg step in shutterless mode for two different angles of detector. CBF files were transformed to ESPERANTO format and treated by CrysAlis v38.41 software. High-resolution reciprocal space maps were produced by locally developed software of ID28 beamline. Images were binned by SNBL Tool Box software and integrated with the Dioptas program. Powder data refinement was carried out using FullProf.Single-crystal data were collected at the ID28 diffraction side station of the European Synchrotron Radiation Facility, equipped with a PILATUS3 X 1M detector mounted on the rotating arm of a Euler goniostat . In all 4TiOF3 particles were investigated by XRD (including high resolution XRD) and SEM. 4TiOF3. The shape of the obtained particles was established SEM: they are octagonal prisms with a base diameter of 3.8–5.6 µm and a thickness of 1.5–2.5 µm  to obtain anatase mesocrystals and study the processes of its transformations upon heating, thermal analysis with mass spectrometry was carried out  were evaluated as a = 4.5954(5) Å and c = 2.9599(8) Å, while the TiO2 derived from other material derived from precursor without fluorium demonstrate a = 4.591 Å and c = 2.957 Å [2 rutile phases were almost the same. It should be noted that the lattice parameters for mesocrystalline anatase differed from those for TiO2 obtained from precursor without fluorium: a = 3.791(1) Å vs. 3.785 Å and c = 9.48(0) Å vs. 9.514 Å [It is known that the anatase–rutile phase transition temperature in a bulk crystal is close to 600 °C . To dete pattern a, anatasulk TiO2 . The incrding to , the pha 2.957 Å . The lat 9.514 Å . It has 2Ti6O13 [2Ti6O13 phase. A similar result had been obtained earlier in the synthesis of anatase mesocrystals in a PEG 6000 matrix after annealing at a temperature of 500 °C [2 layers, which was confirmed by the growth of nanowires along the (100) and (010) planes. The formation of the TiO2–K2Ti6O13 hybrid material with different morphologies was presumably due to the presence of potassium in the PEG 400 polymer matrix. TiO2 is a well-known ion-change nanomaterial [On both diffraction patterns and Raman spectra of the samples after annealing at temperatures of 800, 1000 and 1200 °C, an impurity was observed, identified as potassium hexatitanate K2Ti6O13 ,18,19  phase significantly increased the photoactivity response. Thus, the PCA of mesocrystals after annealing at 800 °C was 4.4 times higher than after annealing at 450 °C. A number of works [2Ti6O13. It was also shown that the photoactivity of the TiO2–K2Ti4O9 hybrid material was almost two times higher than that of pure TiO2 [2Ti6O13 from TiO2 required temperatures above 800 °C or a long duration of synthesis [2–K2Ti6O13 hybrid material in mesocrystals occurred upon heating for 8 h at a temperature of 500 °C [2 began to destroy at 1000 °C, and after annealing at 1200 °C. The XRD and Raman spectroscopy data (On the one hand, the appearance of the potassium hexatitanate (Kof works ,18,22,23ure TiO2 . As for ynthesis ,26,27,28f 500 °C . On the opy data  make it 2-anatase close to 1200 °C. This research for the first time verified that the transition of the mesocrystalline anatase to rutile phase occurs between 1000 °C and 1200 °C, which is over 400 °C higher than transition of bulk TiO2 due to the used precursors. A small amount of K-phase nanowhiskers, which was issued after 800 °C in the TiO2-based composite, stimulated the enhancement of the photocatalytic performance four times. This capability offers a new approach to constructing composite Ti-O layered materials and provides strong potential for the resulting nanomaterial for application in catalysis and electrode materials.In summary, preparation of photoactive oriented nanomaterials based on titanium dioxide and nonionic polymer was successfully realized. The study demonstrated the stability of obtained layered TiO