The initial thickness of the Nb layer determines that of the crystal layer. SEM and TEM observations reveal that the surface is densely covered with well-defined polyhedral crystals. Each crystal is connected to neighboring ones through the formation of tilted grain boundaries with Σ3 (2–1–1) = (1–21) symmetry which show small degradation in lithium ion conductivity comparing to that of bulk. Furthermore, the sub-phase formation at the interface is naturally mitigated during the growth since the formation of Nb2O5 thin film limits the whole reaction kinetics. Using the newly developed stacking approach for stacking solid electrolyte layer on the electrode layer, the grown crystal layer could be an ideal ceramic separator with a dense thin-interface for all-solid-state batteries.In this work, we demonstrate the direct growth of cubic Li Thin-film type solid-state batteries have been prepared using thin film electrodes (micron- or submicron-order) prepared by physical vapor deposition approaches, including sputtering and pulsed laser deposition4. They have been commercialized and shown to be capable of >10,000 charge–discharge cycles5. To further increase the energy density of batteries, many researchers are currently focusing on bulk-type solid-state batteries. However, these batteries are known to have key performance problems. In particular, two issues are directly connected with the power density of batteries: the bonding of solid-solid hetero-interface between electrode and solid electrolyte, and thinning of the solid electrolyte separator8.All-solid-state rechargeable lithium ion batteries using oxide-based solid electrolytes have the potential to drastically improve the high energy, high power and safety of current lithium-ion batteries3xLa2/3−x□1/3−2xTiO3 (LLTO), LISICON, and NASICON have been widely investigated. In particular, garnet-type Lix7−La3Ax2−4+Bx5+O12  derivatives are considered promising candidate materials due to their high Li+ conductivity (around 10−4 S cm−1 at room temperature) and wide electrochemical window. They are neither oxidized nor reduced in a wide voltage range13. The control of balance in the Li+-occupying sites of tetragonal-24d/octahedral-96h is found to be primarily responsible for both the Li+ conductivity and stability under air moisture. Furthermore, Narayanan et al. demonstrated that incorporating external defects, such as replacing Y with Nb (Li5+2xLa3Nb2−xYxO12), enhanced the Li+ conductivity by two orders of magnitude in Li5La3Nb2O1214.Various oxide electrolytes, such as perovskite-type Li16. Existing literatures on solid-solid homo- and heterojunction formation suggest that lowering the reaction temperature is effective for suppressing the sub-phase formation, promoted by the introduction of a buffer layer into the interface8 or using new discontinuous heating processes5. However both these conventional and new heating process under historical powder-based process often have technical limitations on the thinning of dense sintering bodies, as comparing to that of vacuum phase processing. Since the densification reaction is caused by diffusion of chemical species in solids based on the chemical potential gradient formed at the boundary of the contact interface between individual particles, the filling of the raw material powder closely in a crucible at the preliminary forming stage before sintering effectively form a dense sintered body densely. Furthermore, the use of raw materials having a non-uniform shape also makes it difficult to effectively fill the voids.It is generally believed that practical all-solid-state lithium ion batteries should ideally be fabricated by a solid-phase process for achieving dense solid interfaces. Since the architectures at interface, including both material density and purity, strongly affect the electrochemical performance and interfacial resistance, we need to consider how to bond interfaces of polycrystalline ceramic powders while suppressing the side reactions that increase the interfacial resistance18, radio-frequency magnetron sputtering19, sol-gel process20, and aerosol deposition21 have been reported. Even though it was expected that such solid electrolyte thin film provides low electrical resistance and increasing volumetric energy density for all-solid-state battery, their lithium ion conductivities at room temperature were in the range of 10−7–10−5 S·cm−1, which is nearly two digits lower than sintered pellets samples. These film fabrication methods are efficient for fabricating uniform film and controlling the film thickness, however in some cases, it is difficult to control elementary composition and microstructures. Especially, except for epitaxial growth on a single crystal substrate18, there is no effective way for controlling the crystal growth orientation and grain boundary structures. Moreover, increasing substrate temperature during deposition and/or post-annealing should be needed to obtain well-crystallized films. Since high temperature treatments may lead to undesired reactions at the interface or uncontrolled diffusion between electrode and solid electrolyte, these methods are not recommended in some cases for fabricating all-solid-state batteries.Very recently, solid electrolyte thin films, fabrication by using pulsed laser deposition (PLD)5La3Nb2O12 crystal layers that are less than 30-μm thick, via the conversion of ultra-thin Nb substrate in a LiOH flux. We further discuss the reaction mechanism and crystallographic characteristics related to the crystal layer formation based on cross-sectional electron microscopic analysis. In addition, heterojunction formation between Li5La3Nb2O12 and LiCoO2 ceramics  was performed through a similar approach.Based on the above considerations, here we demonstrate the formation of cubic phase stoichiometric Li5La3Nb2O12 crystal layers were prepared on a Nb substrate by the flux growth method using a LiOH flux, in which LiOH·H2O and La2O3 powders reacted with the Nb substrate. Time-dependent XRD measurements were performed. As shown in Fig. 5La3Nb2O12 was initiated at 500 °C for 1 min. The diffraction lines were assigned to cubic phase Li5La3Nb2O12, perovskite LiLa2NbO6, and Nb, respectively. Perovskite LiLa2NbO6 is considered an intermediate phase which lacks Li and La compared to the stoichiometric composition of Li5La3Nb2O12. In fact, there are no reports on the formation of stable LiLa2NbO6 phase during the synthesis of Li5La3Nb2O12. Neither is the LiLa2NbO6 phase found in the ternary phase diagram of Li2O-La2O3-Nb2O5 system22. We further carried out computational studies to predict the LiLa2NbO6 phase formation in Li2O-La2O3-Nb2O5 system under various temperatures and pressures. As shown in Fig. 2NbO6 phase was not formed when the starting materials were mixed in either stoichiometric or non-stoichiometric compositions. All these results indicate that the LiLa2NbO6 phase is not thermodynamically stable.The Li5La3Nb2O12 progressed with increasing holding time. The cubic phase Li5La3Nb2O12 was obtained as a single phase after 10 h. It is interesting to note that the Li5La3Nb2O12 phase was the major product during the early stages of the reaction, despite the unreacted La2O3 and LiOH remaining in the flux. Furthermore, no diffraction pattern assignable to niobium oxides such as Nb2O5 was detected during the growth process. In contrast, in-situ XRD measurement in atmosphere without using the LiOH flux revealed that the metal Nb substrate surface was oxidized to Nb2O5 at 500 °C 25.Next, we carried out time-dependent SEM observations coupled with XRD measurements to further understand the reaction and growth mechanisms Fig. . Two dif2NbO6 through the reaction of LiOH·H2O and La2O3 powders with Nb2O5 layer limits the whole reaction, LiLa2NbO6 and/or Nb2O5 layer should remain at the interface. Thus, the thickness of Li5La3Nb2O12 crystal layer will be determined by the initial thickness of the oxidized Nb layer prior to the reaction. Indicating that the self-diffusion rate of Nb is not much faster than the diffusion of O2 in the molten LiOH flux. If the self-diffusion rate of Nb is much faster than the diffusion of O2 in the molten LiOH flux, the anisotropic atomic motion at the boundary layer, which is a consequence of the different diffusion rates, will prompt the formation of voids and spaces at the interface.Cross-sectional SEM observation revealed that the polyhedral crystals grew directly from the Nb surface Fig. . There w5La3Nb2O12 crystal layer which was created using FIB-milling. The cross-sectional TEM images and SAED patterns are shown in Fig. 5La3Nb2O12 crystal layers. Superimposed on it are the stereo diagrams for the case where the incident [211], [110], and [210] incidence as the poles from cross-sectional TEM observation. It can be seen that the crystal planes {120} and {112}, which appeared on the surface at each incidence angle, are close to each other and enclosed by the circle in the figure. This result suggests that there may be a direct correlation with crystal orientation of crystal habit which appears in different grains.Cross-sectional SEM observation also indicates that each individual crystal seems to connect to neighboring crystals through the formation of tilted grain boundaries. In order to characterize their 3D crystallographic orientation in the selected area near the grain boundaries, we performed cross-sectional TEM observations of the sliced Li+ conductivity of the sinter bodies prepared from the Li5La3Nb2O12 crystals of which it was grown from LiOH flux under same recipe described in this paper25. The Li+ conductivity was of 5 × 10−6 S·cm−1 at room temperature, as evaluated by conventional electrochemical impedance spectroscopy. Unfortunately, reproducible data on the Li+ conductivity for the Li5La3Nb2O12 crystal layers have not yet to acquire because any symmetrical cells, Li| Li5La3Nb2O12 crystal layer|Li for non-blocking geometry and Au | Li5La3Nb2O12 crystal layer |Au for blocking geometry were not obtained at this time. It is difficult to make free-standing film required for making symmetrical cells due to the strong adhesion strength to the Nb substrate. We are now going to demonstrate AC impedance measurement of the Li5La3Nb2O12 crystal layers by using micro-probe technique26. We will report our new findings near feature in elsewhere soon.We have reported the Li−2, which is markedly smaller than that of cubic-Li7La3Zr2O12 (0.52 J m−2)27. It indicates that the tilted grain boundary represented by the Σ3 (2–1–1) = (1–21) models is one of the most stable grain boundaries in the Li5La3Nb2O12 system. This computationally predicted trend is consistent with the thermodynamically stable faces of the Li5La3Nb2O12 crystals grown from a molten LiOH flux25.A stoichiometric equilibrium atomic model was calculated by using MD simulation for understanding the atomic arrangement and determining the Li ion conductivity at the tilted grain boundary of Σ3 (2–1–1) = (1–21), as a one representative grain boundary model. Figure + conductivities of the bulk and the Σ3 (2–1–1) = (1–21) models, including the average and separate conductivities along the a, b, and c axes. It should be noted that the Li+ conductivities of the utilized grain boundary model included bulk conductivities, because of the presence of bulk regions in the model. The corresponding Li+ diffusion coefficients and conductivities at a specified temperature can be evaluated from the slopes of MSD plotted against time and the Nernst-Einstein equation, respectively. The values of the fitted Li ionic conductivity at 300 K, which were obtained from the Arrhenius plots for the models, are summarized in Fig. + conductivity is in good agreement with data in previous reports28. However, it was almost two orders of magnitude higher than the experimental value evaluated by electrochemical impedance spectroscopy for the pelletized samples.Figure 5La3Nb2O12 is lower than the bulk one, regardless of the orientations. In particular, the conductivities along the c-axis (perpendicular to the grain boundary) are the lowest, being one order of magnitude lower than the bulk value. To our best knowledge, this study reports for the first time that the conductivity along the direction perpendicular to the grain boundaries primarily contributes to the reduction in the total ion conductivity. Most previous electrochemical impedance spectroscopic studies of garnet-based solid electrolytes could not distinguish the tilted grain boundary contribution driven by atomic arrangements within the overall material resistance, thus underestimating the experimental bulk conductivity. Furthermore, the elemental substation of Nb with Zr, leading to form Li7La3Zr2O12 was known to enhance bulk Li+ conductivity through changing the Li+ occupancy at 24d/96 h sites12, we newly discovered that the substitution made significant degradation of the grain boundary conductivity at the Σ3 (2–1–1) = (1–21). Our molecular dynamics simulation to the Li+ conductivity in Li7La3Zr2O12 revealed that the fitted Li ionic conductivity at 300 K were ca. 38.1 mS·cm−1 in bulk and 0.7 mS·cm−1 in the grain boundary. The grain boundary conductivity decreased nearly three orders than that of bulk. It was quite different from the Li5La3Nb2O12 system. We believe our results here strongly suggest that the observed discrepancy between the experimental and computational Li+ conductivities may be attributed to the effect of the grain boundary resistance on the atomic arrangement.The grain boundary conductivity in the cubic Li5La3Nb2O12 crystal layer on LiCoO2 ceramics through the direct growth from the LiCoO2 surface. Sputtered thin Nb film was deposited prior to the growth, and was used as the Nb source instead of a metallic Nb substrate. The LiCoO2 ceramic surface turned to a brilliant color after the deposition. Time-dependent XRD holding at 500 °C reveals that the perovskite LiLa2NbO6 phase was dominantly formed during the initial stage of reaction  formation during the growth. M. Bitzer et al. reported that the formation of unwanted Li0.5La2Co0.5O4 phase at the LiCoO2/Li7Li3Zr2O12 interface of which it appears that La diffused from the Li7Li3Zr2O12 electrolyte into the LiCoO2 cathode during calcination. They further claimed that the Li0.5La2Co0.5O4 phase formation at the electrode/electrolyte interface resulted in significant Li+ conductivity fading29. We believe that the fabrication route which achieve the suppression of sub-phase formation at the hetero-interface will be an ideal avenue to produce thin and dense ceramic separators. In fact, no electrical short-cut was observed in the stacking structures of Li5La3Nb2O12 crystal layer and LiCoO2 ceramics after the deposition of In metal as a counter electrode (an anode).Cross-sectional SEM combined with EDS mapping clearly showed that the elemental distribution in Co is very different from those of Nb and Zr , meaning that the ultra-thin Nb film, sequentially formed Nb5La3Nb2O12 and related compounds on solid substrates. The conversion of Nb substrate in molten LiOH flux formed crystal layers with well-defined faces, and each individual crystal is connected to neighboring ones. Cross-sectional TEM observation coupled with SAED pattern analysis implied the formation of tilted grain boundaries that are composed of [211], [110], and [210] faces. We further found that the ultra-thin Nb film naturally mitigates sub-phase formation at the interface during the growth process, since the formation of niobium oxides on the substrate limits the reaction kinetics. We believe that our approach having robustness against side reactions at the interface could possibly lead to the production of ideal ceramic separators with a thin and dense interface. The LiCoO2 ceramics used in this study (1 mm in thickness) was too thick for solid batteries and could not perform as such at this stage. However, as long as the electrode layer can be made as thin as 100 μm, the stacking layer will operate as a solid battery.We have studied the direct growth of cubic Li2O3, and LiOH·H2O  were used for the preparation of the Li5La3Nb2O12 crystal layer. The Nb substrate was cut into small pieces with dimension of 10 mm × 15 mm prior to use. LiCoO2 ceramics (φ = 13 mm × 1 mm thick) were purchased from KCM Corporation. All commercial materials were used without further purification.Metal Nb substrate (Nilaco Corporation) Laθ = 10–80°. For the cross-sectional TEM observation and crystallographic orientation analysis of the Li5La3Nb2O12 crystal layer on Nb substrate, thin specimens were prepared by a focused ion beam apparatus with Ga gun . Selected area electron diffraction (SAED) patterns and bright-field TEM images were obtained using a 200kV electron microscope (TOPCON EM-002B).The morphological and elemental mapping analyses of the grown crystal layers were carried out using field-emission scanning electron microscopy (FE-SEM) coupled with an analyzer for energy dispersive X-ray spectroscopy (EDX) . An acceleration voltage of 15 kV was used. Pass energy was controlled to be The phases and structures of the crystals were identified using X-ray diffraction (XRD) analysis with Cu Kα radiation. The X-ray diffractometer  was operated at 30 kV and 20 mA, with 25La3Nb2O12 single crystals the crystal layer formation25. La2O3 (0.305 g) and LiOH·H2O (0.295 g) were mixed in an alumina crucible 30 mL in volume for 30 min. To adjust the solute concentration to 5 mol%, 2.431 g of LiOH·H2O powder was further added as a flux. A Nb substrate was gently placed a the mixture and then heated to 500 °C at a rate of 500 °C·h−1 in an electric furnace. The substrate was cooled to 300 °C at a rate of 100 °C·h−1, and then naturally cooled to room temperature in the furnace. The substrate was separated from the mixture by washing with warm water for three times to remove the remaining flux, completely. Finally, the substrate was dried at 60 °C in air for 10 h.We applied similar recipe of the flux growth of polyhedral shaped Liab initio simulation package31 was used with the generalized gradient approximation (GGA-PBE sol) + U32 and projector-augmented wave methods33. For the GGA + U calculations, the U value for the d-orbitals of Nb was set to 1.5 eV, based on previous reports34. An energy cutoff of 500 eV and a k-point mesh were chosen, so that the product of the number of k-points and the number of atoms in the unit cell was greater than 1000. To construct the phase diagram of the Li-La-Nb-O system, we obtained the possible compositions from Inorganic Crystal Structure Database (ICSD) and optimized the structures of related oxides . The total energy, Etotal (X), obtained by DFT calculations was assumed as the sum of chemical potentials μ(Y): Etotal (Li5La3Nb2O12) = 5(Li+) + 3(La) + 2(Nb) + 12(O). The chemical potential of oxygen molecule was set as zero in the horizontal axis, and that of lithium metal was set as zero in the vertical axis. The energy correction for O2 molecules was used for all calculations as reported by Wang et al.35. At the boundaries between two phases, the chemical potentials of each atom were assumed to be equal in the two phases. The boundaries between two phases were calculated by simultaneous equations. For example, the boundary between Li5La3Nb2O12 and (La3NbO7 + Nb2O5) phases was calculated by the following equations:36,2 molecule obtained by DFT calculations. 2 phase under the standard pressure 37.The Vienna 38. The long-range Coulombic interactions were summed via the Ewald method39, whereas the short-range interactions were described using the parameterized Buckingham pair potentials40. The latter were summed to the cut-off value of 10.5 Å, beyond which the influence of the potential was considered negligible. The lattice energy is defined asi and j, qi and qj are the ion charges, and 41.Molecular dynamics (MD) simulations were performed using a Born-like description of the ionic crystal lattice42 was used for all MD calculations, and the corresponding time step was equal to 1 fs. First, the initial models were equilibrated for 20 000 time steps (20 ps) in the isothermal isobaric (NPT) ensemble at a temperature of 300 K. During this initial period, the volume of the cell was allowed to relax with time. The Nosé-Hoover thermostat and barostats44 were used to control the temperature and pressure, respectively. Afterwards, the temperature was elevated from 700 to 1700 K at a rate of 10 K per 5 ps; and the NPT dynamic simulations were conducted for 100 ps, during which the cell angles were allowed to relax. After equilibration at 1700 K, the obtained structure was cooled to a desired temperature, which allowed the lattice to fully equilibrate in a shorter simulation time compared to that required for directly heating the system to the target temperature. Cooling was performed via an iterative procedure, which involved decreasing the temperature in steps of 10 K accompanied by dynamic simulations with durations of 5 ps. For each studied temperature, MD simulations containing 500 000 time steps (500 ps) were performed using the constant volume and temperature (NVT) ensemble, in order to obtain statistical information about diffusion rates. The bulk Li5La3Nb2O12 calculations were performed using the 3 × 3 × 3 unit cell superstructure with cubic symmetry and containing 4752 atoms.The DL POLY simulation packageA is the GB area, EGB is the lattice energy of the GB model, Ebulk is the lattice energy per atom, and N is the number of atoms in the particular GB model. To investigate the ionic transport properties of a particular structure, the mean square displacement (MSD) of the ions was monitored as a function of time at different temperatures. For a system with N ions, the MSD of ion i at position ri(t + t0) and time t with respect to its initial position ri(t0) is defined asThe GB energy, D, can be calculated from the MSD slopes plotted against time45:46:F is Faraday’s constant, R is the gas constant, and T is the temperature. The Li ionic conductivity values were obtained in the temperature range of 700–1700 K.The Li diffusion coefficient, 2 ceramics by RF-driven Ar sputtering under 0.67 Pa. The back pressure, input power, and flow rate of Ar gas were controlled to be 2.0 × 10−3 Pa, 300 W, and 3.0 sccm, respectively. The 1 mm thick LiCoO2 ceramics with sintering density of >98% was gently placed on the mixture of La2O3 (0.305 g) LiOH·H2O (0.295 g) and then heated to 500 °C at a rate of 500 °C·h−1 in an electric furnace. After maintaining this temperature for a designated period, the crucible was cooled to 300 °C at the rate of 100 °C·h−1, and then naturally cooled to room temperature in the furnace. The substrate was separated from the mixture by washing with warm water for three times to remove the remaining flux. Finally, the substrate was dried at 60 °C under air for 10 h.A thin Nb film was deposited on the LiCoOsupplementary information


SPW1 and OsMADS2 transcription factors. In the superwoman1‐cleistogamy1 (spw1‐cls1) mutant, SPW1 is impaired for heterodimerization with OsMADS2 and consequently spw1‐cls1 shows thin, ineffective lodicules. However, low temperatures help stabilise the mutated SPW1/OsMADS2 heterodimer and lodicule development is restored when spw1‐cls1 is grown in a cold environment, resulting in the loss of the cleistogamous phenotype. To identify a novel, temperature‐stable cleistogamous allele of SPW1, targeted and random mutations were introduced into the SPW1 sequence and their effects over SPW1/OsMADS2 dimer formation were assessed in yeast two‐hybrid experiments. In parallel, a novel cleistogamous allele of SPW1 called spw1‐cls2 was isolated from a forward genetic screen. In spw1‐cls2, a mutation leading to a change of an amino acid involved in DNA binding by the transcription factor was identified. Fertility of spw1‐cls2 is somewhat decreased under low temperatures but unlike for spw1‐cls1, the cleistogamous phenotype is maintained, making the line a safer and valuable genetic resource for gene containment.Outcrossing between cultivated plants and their related wild species may result in the loss of favourable agricultural traits in the progeny or escape of transgenes in the environment. Outcrossing can be physically prevented by using cleistogamous (i.e. closed‐flower) plants. In rice, flower opening is dependent on the mechanical action of fleshy organs called lodicules, which are generally regarded as the grass petal equivalents. Lodicule identity and development are specified by the action of protein complexes involving the  Oryza sativa L.) stigmas and pollen mature before flower opening, thereby promoting self‐pollination. Outcrossing rates in cultivated rice are estimated to be less than one per cent  followed by two domains involved in protein–protein interactions  and a C‐terminal domain supporting different functions, notably transcriptional control  into female (i.e. carpel‐like) organs, hence the superwoman1 gene designation  organ transformation, a phenotype also referred to as ‘superman’  allele, the isoleucine in position 45 of the SPW1 protein is replaced by a threonine  and OsMADS2. Both proteins are encoded by MIKC‐type MADS‐box genes and consist of a highly conserved N‐terminal DNA‐binding domain  belongs to a hydrophobic β‐strand involved in dimerisation with OsMADS2 and thus mutations at this position were initially favoured in the experimental design. A total of 11 cDNAs encoding for amino acids with gradually decreasing hydrophobicity indices were designed, including amino acids with charged , aromatic (I45Y) and unique (I45G) side chains. The binding affinities between OsMADS2 and each of the mutated SPW1 proteins were estimated from the resulting colouring intensities in the filter assay. It was hoped to identify mutations slightly more severe than in spw1‐cls, which would correspond to coloration intensities somewhat weaker than the one obtained for the SPW1I45T control. In our experimental conditions, filter spots corresponding to the SPW1WT, SPW1I45T and empty vector controls showed a strong, fair or no coloration, respectively (Table I45T control. Substitution with cysteine (C) also resulted in a faint colouring. These results indicate that up to now the investigated mutations had either too weak or too strong effects over SPW1/OsMADS2 dimerisation to be considered candidates for a prospective genome editing.With the recent techniques collectively referred to as genome editing, directed mutagenesis in a plant genome is becoming possible , two clones for both the MADS and the K domains , and two other clones for both the K and the C‐terminal domains . The remaining four clones each carried a single mutation affecting the MADS domain , the I domain (I67T), or the K domain (W80R).To test for mutations outside the 45th position of the SPW1 protein, a random mutagenesis strategy was followed and a yeast two‐hybrid library of I45T in a liquid β‐galactosidase assay. β‐Galactosidase activities ranged from about 35% to 90% to that of the SPW1I45T/OsMADS2 dimer, indicating that the screen was successful in identifying mutations with intermediate destabilising effects  and the resulting constructs were used to complement the spw1‐1 null mutant, along with wild type (WT) and spw1‐cls controls. A minimum of 24 transgenic lines were generated and scored for floral organ development for each of the seven constructs.To evaluate to what extent the newly identified mutations would actually affect floral development, five mutants spanning the obtained range of β‐galactosidase activities  were selected for testing cls‐like) phenotype or a loss‐of‐function phenotype, indicative of a partial and lack of complementation, respectively; the remaining 17% of the lines showed a ‘superman’ phenotype, indicative of overexpression of the transgene  showed for the most part a loss‐of‐function phenotype and were completely sterile , was isolated from a chemically mutagenised rice population (cv Kita‐aoba). In contrast to the WT, stamen exertion could not be seen in cls2 . The cls2 and spw1‐cls alleles were therefore renamed to spw1‐cls2 and spw1‐cls1, respectively.The spw1‐cls2 line, plants were grown in paddy fields in three locations of Japan: Tsukubamirai, Joetsu and Sapporo, in order of increasingly colder climates. Preliminary data indicate that the fertility of spw1‐cls2 is negatively affected by low temperatures, with about 90% (Tsukubamirai), 75% (Joetsu) and 65% (Sapporo) of the wild type fertility. Further study in Tsukubamirai showed that spw1‐cls2 was comparable to the WT for heading date, culm number and length, panicle length and spikelet number  and GLOBOSA (GLO) are the respective orthologs of SPW1 and OsMADS2. The DEF/GLO heterodimer has been shown to bind efficiently a CArG box located in the DEF promoter region . A pronounced band shift was observed in the lane loaded with the WT heterodimer, confirming that the DEF‐CArG probe is significantly bound by SPW1WT/OsMADS2 spw1‐cls1 is caused by a destabilisation of the SPW1I45T/OsMADS2 dimer . It is thought that low temperatures allow the SPW1/OsMADS2 heterodimer stabilising, resulting in the recovery of the activity of related transcriptional complexes  open flowers.The ability to prevent cultivated plants from outcrossing with plants of the environment is of particular importance in modern agriculture, all the more so in the light of the environmental concerns expressed by the scientific community and the general public regarding the development and commercialisation of GM crops  change. Flower development in all these three mutants is severely altered, indicating a loss of function of the mutated proteins . All yeast transformations were performed using Mav203 as the host strain as described previously . For quantification of β‐galactosidase activity, yeast cells were grown in liquid cultures to log phase at 25 °C unless otherwise stated and ONPG was used as substrate as described in  under standard conditions. Cleistogamous plants were selected following the method described by Yoshida et al.  with a 26 °C/20 °C day/night temperature regime. A minimum of 15 seeds were sown in three‐litre circular plastic pots with 0.9 g each of N, P2O5 and K2O. At panicle formation stage, pots were transferred to a temperature gradient chamber. Six pots of each line were placed in different positions along the temperature gradient. Open flowers were scored and marked every two to three days and the total number of flowers was counted after full maturation.Plants of spw1‐cls2, including flower opening rate and fertility, plants were cultivated under standard conditions in paddy fields of the NARO Institute of Crop Science , NARO Agricultural Research Center  and NARO Hokkaido Agricultural Research Center  during summers of 2011 and 2012.To evaluate the agronomic characteristics of DEFICIENS CArG box (5′‐GGCAACTCTTTCCTTTTTAGGTCGCATATGG‐3′) was labelled with digoxigenin using a DIG gel shift kit reagents (Roche) and 100 fmol of the probe was treated with 0.03 units of proteinase K (Sigma P2308) for 30 min at 37 °C followed by a 60‐min deactivation at 60 °C to remove DIG transferase contamination from the probe sample. A total of about 1 μg of protein was put in presence of 20 fmol of labelled probe for 20 min at 25 °C in a 20 μL binding solution containing 2.5% glycerol, 5 mm MgCl2, 50 ng Poly (dI·dC) and 0.05% NP‐40 and 1X binding buffer (Thermo Scientific 20148A). Samples were loaded on a 6% polyacrylamide gel and detected after blotting in a chemiluminescent reaction using a LAS‐3000 imager (Fujifilm).For each protein, the corresponding full‐length CDS was cloned into a pF3A‐WG expression vector (Promega). Each one of the three  proteins was co‐synthesised with OsMADS2 using a TNT SP6 High‐Yield wheat germ protein expression system (Promega) according to the manufacturer's instructions. A synthetic probe corresponding to a Figure S1 Spikelet of the F1 progeny of a spw1‐cls and cls2 cross. The lemma has been removed to allow observation of the inner organs. Bar = 2 mm.Click here for additional data file.


The system is of interest as a model for fundamental electrolyte–electrode and dye‐sensitized solar cells. The initial interaction involves degradation of the [BF4]− anion, resulting in incorporation of F into O vacancies in the anatase surface. At low coverages, [C4C1Im][BF4] is found to order at the anatase(101) surface via electrostatic attraction, with the imidazolium ring oriented 32±4° from the anatase TiO2 surface. As the coverage of ionic liquid increases, the influence of the oxide surface on the topmost layers is reduced and the ordering is lost.The interaction of the ionic liquid [C Ionic liquids (IL) are room‐temperature (RT) molten salts comprised entirely of cations and anions.2, a wide band gap semiconductor that is non‐toxic, highly resistant to corrosion, has both chemical and mechanical stability and has very low manufacturing costs. The most efficient DSSCs currently use an electrolyte involving a REDOX couple  have attracted a great deal of interest.2.4C1Im][BF4]) with the anatase TiO2(101) surface.Both the function and performance of devices employing ILs depend on the behavior of the IL at phase boundaries, interfaces and near interfacial areas.4C1Im][BF4]  and the 4 Å IL film . The ionic liquid [C1C4Im][BF4] , shown in Figure 2(101) surface via thermal evaporation in vacuum. The individual elemental spectra are recorded at varying photon energy so that the kinetic energies of the photoemitted electrons are roughly the same. This ensures that an equivalent depth of IL is sampled for all elements. For the full experimental method please see the Supporting Information, S.1. The film thickness was calculated from the attenuation of the Ti 2p signal following adsorption of the ionic liquid, . The calculation assumes that the IL film grows in a uniform layer‐by‐layer manner.Figure The XPS core‐level data for the 30 Å film are comparable to those recorded from bulk ILs and therefore this film can be seen to be representative of the bulk IL.4C1Im][BF4] can be deposited intact onto the anatase TiO2(101) surface, by evaporation at a temperature of around 220 °C, in agreement with a previous adsorption study on Cu.There are two nitrogen atoms per ion pair, both located in the ring. The differing length of the side chains does not result in a significant change in the chemical environment so the N 1s spectrum should be fitted with a single species.4C1Im]+ cation layers adsorb intact on the TiO2 surface. The components arising from C1, C2 and C3 are shifted by 0.3 eV to lower binding energies relative to the thick film. This binding energy shift is not observed in the peak arising from carbon, C4. The shift to lower binding energy of C1, C2 and C3 derived features can be attributed to the interaction of the imidazolium ring with the surface. It has been reported that the binding energy of molecular orbitals at metal/organic interfaces can vary as a function of the overlayer thickness.For the 4 Å film, the C 1s spectrum has a different shape, but can still be fitted well with the same four components seen in the thick film. The peak intensity ratios of 0.12±0.02:0.25±0.01:0.25±0.01:0.37±0.02 are also in excellent agreement with the expected stoichiometry. This suggests that the initial − resulting in the formation of Ti‐F species, the XPS data suggests that the [C4C1Im][BF4] IL undergoes no chemical interaction with the surface and bonds to the anatase(101) surface solely via electrostatic attraction. See S.4, for a table summarizing all peak assignments, their respective binding energies and their relative abundancesIn the F 1s spectrum of the 4 Å film, two peaks are observed at binding energies of 686.4 and 684.6 eV. The lower binding energy peak is consistent with the formation of Ti–F species at the surface.4C1Im][BF4] film adsorbed on anatase TiO2(101), recorded using a multichannel partial yield detector. In all spectra, the first sharp resonance occurs at a photon energy of 401.9 eV. This feature arises from a N 1s→π* transition.4C1Im][I], for both the C K edge and the N K edge. Figure ° relative to the surface. Analysis of the C K edge data gives a tilt angle in agreement with the N K edge data . This result is at odds with calculations for adsorption of [C2C1Im][[SCN] or [C2C1Im][B(CN)4] on the anatase TiO2 surface, where both molecules showed some adsorption with the plane of the cation perpendicular to the surface.4C1Im] cation studied here, the aliphatic side chain is longer and perhaps more likely to be oriented away from the hydrophilic TiO2 surface. Furthermore, the calculations considered a perfect stoichiometric TiO2 surface whereas the photoemission data indicates that F ions become attached to the TiO2 surface. This may also be a factor in determining the orientation of the cations. For the thick film, NEXAFS spectra in Figure 4C1Im][BF4],Figure 4C1Im][BF4] with the anatase TiO2(101) surface has been investigated using a combination of XPS and NEXAFS spectroscopy. At low coverage, the IL adsorbs in an ordered manner, with the imidizolium ring oriented 32±4 ° from the anatase TiO2(101) surface. In addition to this, the [BF4]− anion is seen to undergo surface‐induced degradation, leading to the production of Ti‐F species on the surface, most likely reacting with the surface at O‐vacancy sites. This is illustrated schematically in Figure The interaction of CC1Im[BF4]As 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.SupplementaryClick here for additional data file.


We then discuss in detail the three main facet‐controlled synthetic strategies  to fabricate Cu2O‐based nanocrystals with heterogeneous, etched, or hollow structures, including a number of important concepts involved in those facet‐controlled routes, such as the selective adsorption of capping agents for protecting special facets, and the impacts of surface energy and active sites on reaction activity trends. Finally, we highlight the facet‐dependent properties of the Cu2O and Cu2O‐based nanocrystals for applications in photocatalysis, gas catalysis, organocatalysis and sensing, as well as the relationship between their structures and properties. We also summarize and comment upon future facet‐related directions.Shape‐dependent catalysis and sensing behaviours are primarily focused on nanocrystals enclosed by low‐index facets, especially the three basic facets . Several novel strategies have recently exploded by tailoring the original nanocrystals to greatly improve the catalysis and sensing performances. In this Review, we firstly introduce the synthesis of a variety of Cu Besides the various routes for the synthesis of NCs, several novel strategies have recently exploded by carving, modifying, or transforming the original NCs that greatly improve the catalysis and sensing performances.2 by hydrogenation. The disorder‐engineering substantially improved the solar photocatalytic performances of TiO2. R. Long et al.2 supports. By changing the light intensity irradiated on Pd–TiO2 heterogeneous structures, the charge condition of the Pd surface could be rationally modulated, and thus the function of Pd nanocubes in organic oxidation reactions and O2 activation could be tailored. Our group2O octahedra as templates. The obtained amorphous NiCo2.7(OH)x nanocages displayed outstanding applications in electrochemical water oxidation.In addition to the shapes of nanocrystals (NCs), their surface conditions (surface energies and electronic structures) also determine their physical and chemical properties.rcentage % of high2O nanomaterials, with unique optical and electrical properties,2 reduction,2O nanowires2O polyhedra enclosed by high‐index planes,2O polyhedra enclosed by low‐index planes2O NCs, especially in cubic, octahedral, and rhombic dodecahedral crystals , to tailor their facet‐dependent properties. It is noteworthy that although smaller NCs possess higher activities in catalysis and sensing than larger NCs, the reported activity of of smaller Cu2O NCs2O NCs; thus, larger Cu2O NCs are often used as precursors for further carving, modifying and transforming.In this context, the inexpensive, non‐toxic and abundantly available Cu2O‐based NCs as well as tailoring their facet‐dependent properties of catalysis and sensing. We begin with a brief discussion of solution phase synthetic strategy of the three basic Cu2O NCs  and Cu2O NCs enclosed by high‐index planes, as well as the key role of CA for controlling their crystallographic facets. We then introduce in detail the three main facet‐controlled synthetic strategies  on the Cu2O NCs to fabricate Cu2O‐based NCs with heterogeneous, etched, or hollow structures, and discuss in detail a number of important concepts involved in those facet‐controlled routes, including the selective adsorption of CA for protecting special facets, and the impacts of surface energy and active sites on reaction activity trends. Finally, we summarize the exciting facet‐dependent properties of Cu2O and Cu2O‐based NCs for applications of photocatalysis, gas catalysis, organocatalysis and sensing, as well as the relationship between their structures and properties. We expect that this review will inspire facet‐controlled methodologies, and more examples of these facet‐dependent properties should be continuously explored, endowing nanomaterials with excellent properties for numerous applications.In this review, we comprehensively summarized the recent progresses in facet‐controlled synthetic strategies for the preparation of Cu22O crystallizes in a cubic structure. A tetrahedron of Cu atoms encircle every O atom, and every Cu atom possesses two neighboring O atoms as illustrated in the model of unit cellFigure2O crystals, it is well established that the surface energy is closely related to the density of under‐coordinated Cu atoms.2O are illustrated in Figure 2O are in the following order: γ{100} < γ{111} < γ{110}.Cu2O NCs are distinctly different. For example, the {311}, {522} and {211} facets can be displayed by a terrace × step as 2 {100} × {111}, 3 {100} × 2 {111}, and {100} × {111}, respectively. That is, they possess two {100} terraces and one {111} step, three {100} terraces and two {111} steps, and one {100} terrace and one {111} step, respectively ,FigureCu2O NCs.2O NCs enclosed by low‐index facets. For instance, by using the preferential adsorption of polyvinylpyrrolidone (PVP) on the {111} facets, our groupc‐Cu2O to o‐Cu2O .2O NCs totally enclosed by {110} facets could be obtained. With the increasing concentrations of oleic acid, the morphologies of Cu2O crystals were evolved from c‐Cu2O, o‐Cu2O, {110} truncated o‐Cu2O, to d‐Cu2O. During this process, oleic acid firstly adsorbed on the {111} facets to form o‐Cu2O; with continuous increasing of the concentration of oleic acid, the oleic acid began to adsorb on the {110} crystal planes. The area of the {110} surface was ever increasing, while the {111} surfaces gradually disappeared. Finally, d‐Cu2O enclosed by {110} facets were synthesized. By using sodium dodecyl sulfate (SDS) as CA, M. H. Huang et al.2O NCs with morphology evolution from c‐Cu2O to d‐Cu2O 2 to Cu2O and controlling the pH. By increasing the amount of NH2OH·HCl, the gradually decreased solution pH that caused by the HCl released from NH2OH·HCl would retard the formation rate of Cu2O. The rate for growing c‐Cu2O was within 1 min, but that for d‐Cu2O was decreased to 60 min.To date, CAs have played an important role on shape‐controlled synthesis of NCs,2O Figure4a, whid‐Cu2O. Furthermore, a slower growth rate, namely a kinetic‐controlled process is essential for obtaining high‐index facets. C. Wang et al.2O polyhedral microcrystals partially enclosed by {311} high‐index facets. A low concentration of copper salts as well as a weak reducing agent contributed to the kinetic‐controlled process, and the decreased viscosities caused by the extra ethanol may improve the diffusions of the reactants. Those above factors finally contributed to the generation of the novel configurations. So far, another shape of 50‐facet Cu2O architectures with {311}, {522}, {211} facets,2O polyhedra with {211}, {522} and {744} facets2O polyhedra with {332} facetsThis suggested that a slower growth rate contributed to the generation of 2O polyhedra with smooth surfaces could be easily obtained, which lays a solid foundation for further tailoring and investigation of the facet‐dependent performance.To sum up, by using CA or kinetic‐controlled process, Cu34 enclosed by {110} and {010} facets, photogenerated holes and electrons were transferred to the {110} and {010} surfaces for oxidation and reduction reactions respectively, due to the different energy levels of the two facets. When MnOx  and Pt  were preferentially deposited by light‐induced deposition onto the {110} and {010} facets of BiVO4, the performances of photocatalytic water splitting were significantly improved. They further optimized the experiments to design two highly efficient photocatalyst systems .2O‐based heterogeneous structures have been reported,2O crystals.Recently, numerous studies are focused on the formation of heterogeneous structures by rational growing supported substances  on the support , since metal oxides can not only serve as a support for a better dispersibility of disperse metal nanoparticles (NPs), but also enhance the catalytic abilities by interacting with the metal NPs.o‐Cu2O by employing the preferential adsorption of SDS on {111} facets . The surface energy distribution follows the order of corners > crystal edges > {111} facets, and results in selective growth and evolution of the heterogeneous structures.Edges and corners with a large curvature also play a key role in selective growth. M. L. Du et al.42O to various hollow structures.) To date, various metal or alloys  with the highest active sites. Although Ag2O3 NCs; the etching by oxalic acid preferentially occurred along the [001] direction. Hence, the Fe2O3 NCs with minor {001} and major {110} facets would transform into Fe2O3 discs with minor {110} and major {001} facets.2O NCs, and study the formation mechanisms, including preferentialadsorption, etching, and others.An appropriate CA (ions or molecules) could selectively adsorb on special facets to avoid dissolution. Thus, the existing CA is a critical factor when inferring the reacted facet in the initiation of an etching process. For example, using phosphate ions as CA selectively protected the {110} facet of Fe2O NCs. M. H. Huang et al.2O nanocages and nanoframes with empty {100} or {110} facets from Cu2O truncated rhombic dodecahedra. Because SDS selectively adsorbed and protected the {110} facets, the etching process occurred prior to the {100} facets. Thus, truncated rhombic dodecahedral Cu2O nanoframes consisting of empty {100} facets and {110} skeleton facets (type‐I nanoframe) were formed first  are in the following order: Eapex > Eedge > Efacet, according to the different numbers of coordinated O atoms. Hence, the relative order of ethanol molecules adsorbed on o‐Cu2O should be facet < edge < apex. Therefore, the selective oxidative etching was reversed to the order of adsorption, from the centre of {111} facets, edges, to apexes.In order to obtain more delicate structures, a “pre‐synthesis strategy” has been widely used to carve NCs involving a two‐stage route where NCs acted as precursors for subsequent etching.s Figure b. The can Figure c. As forc‐Cu2O, o‐Cu2O and d‐Cu2O NCs in NH3 solution. The relative stability of different Cu2O crystal facets in NH3 solution in the sequence of {110} < {111} < {100} that were reversed to the order of the surfaces energies. When changing to a weak acid solution2O facets also followed the order of {100} > {111} > {110}, which determined the extent of oxidative dissolution. Stable {100} facets were preserved, but unstable {110} and {111} facets were etched with newly formed {100} facets  as the sacrificial template, to create various hollow, non‐spherical nanostructures, including hollow metal oxides,xSy),2O sacrificial templates, and discuss the three major routes as shown in FigureDue to the large surface area, low density, good surface permeability, and high loading capacity, the shape‐controllable synthesis of hollow/cage‐like nanostructures, even with non‐spherical shapes and regular interiors, has received extensive attention in recent years because of their widespread applications.5.12+/Cu2O (0.203 V vs standard hydrogen electrode (SHE)) than that of the Fe3+/Fe2+ pair (0.77 V vs SHE), Fe(III) ions could instantly oxidize a Cu2O template at room temperature. This redox reaction is showed in Eq. Galvanic replacement is an electro‐chemical process, in which the sacrificial template is oxidized and dissolved in the solution; meanwhile another metal ion with a higher reduction potential would be reduced and deposited on the surface of the template, and finally inherits the original structure.x nanoboxes x core/shell  and PtCl62−/Pt (0.735 V vs SHE) pairs, Cu2O polyhedra could also use for the preparation of nonsperical metal mesocages. F. Hong et al.c‐Cu2O.Amorphous Fe(OH)es Figure9a1 wit2O truncated octahedra, Y. S. Kang et al.2O crystals without the protection of PVP, leading to the formation of hierarchical structures  at room temperature possess at least five stable phases: i.e., chalcocite (Cu2S), djurlite (Cu1.95S), digenite (Cu1.8S), anilite (Cu1.75S), and covellite (CuS).2O‐template route  into the Cu2O suspension, in which Cu2O template is transformed into Cu2O/CuxS core/shell structures at once because of the minimal solubility product constant Ksp of CuxS (Ksp ≈ 10−48).2O core is dissolved completely, and the CuxS shell is kept to the formation of hollow structures.The Kirkendall effect is defined as the migration of the boundary layer between two materials when the two materials have different interdiffusion rates. Due to the faster diffusion rate, voids would be formed in the inner component, which is the most defining feature of the Kirkendall effect.nite Cu1.S, anilit2O crystals as templates, D. S. Xu et al.xS mesocages  with single‐crystalline shells. FigurexS cages. Through a replacement reaction between S2− in solution and O in the Cu2O lattices, Cu2O/CuxS core/shell structures were firstly formed; CuxS mesocages obtained through a subsequently removing the residual Cu2O by ammonia. It is noteworthy that the compositions can be adjusted from Cu2S to Cu1.75S through controlling the reaction atmospheres from N2 to air as shown in Eq. By using Cu7S4 nanoboxes by two consecutive cycles that repeatedly produced Cu7S4 layers in Na2S solution and dissolved the Cu2O core in NH3 solution  coordinate Cu2O polyhedra, various transition metal hydroxides, or oxides with hollow structures could be obtained, perfectly imitating the geometry of the Cu2O template. Z. Y. Wang et al.2 nanoboxes by combining precisely controlled hydrolysis of SnCl4 and simultaneous coordinating etching of the c‐Cu2O templates. During this process, insoluble CuCl intermediate was immediately formed, and dissolved in NaCl solution via coordinating with excess Cl− to form soluble [CuClx]x1−. Eventually, outward evacuation of [CuClx]x1− and inward diffusion of Sn4+ and Cl− through the SnO2 shell lead to formation of intact SnO2 shells and the consumption of Cu2O templates. Based on the Pearson's hard and soft acid–base (HSAB) principle, stable complexes could be formed through the interaction of hard bases with hard acids, and soft bases with soft acids. As a soft acid, Cu+ within the Cu2O templates prefer a soft base ligand  to a hard base  as the coordinating etchant. Recently, our groupo‐Cu2O as the sacrificial template at room temperature. Coordinating dissolution is commonly used for dissolving insoluble materials. For instance, by using certain ligands (CN2S2O3 as the coordinating etchant. S2O32− would coordinate etching Cu2O and form soluble [Cu2(S2O3)x]x2−2, because the soft−hard interaction of Cu+−O2− within Cu2O was weakened compared to the soft−soft interaction of Cu+−S2O32− (Eq. 2+ − S2O32−), metal ions (M2+) were free in the solution. The OH− ions that originated from Cu2O etching 2, Co(OH)2, Ni(OH)2, and Zn(OH)2) could be produced according the CEP route , and small NPs consisted of the MH shell . TEM images of MH nanocages  clearly illustrated their hollow characteristic, and the SAED patterns  demonstrated their amorphous in nature. According to this strategy, amorphous Ni(OH)2 nanoboxesFigure2/reduced graphene oxideWell‐defined MH nanocages (Mn(OH)te Figure11. The62O have mainly been in the realms of catalysis and sensing. In this section, we will focus on the facet‐dependent performances of the three basic Cu2O NCs and such Cu2O‐based NCs for applications of photocatalysis, gas catalysis, organocatalysis, and sensing as well as the relationship between their structures and properties.To date, the applications of Cu6.12O with bandgap of 2.1 eV are expected to be promising materials in visible‐light photocatalytic degradation,2O with their morphology‐dependent photocatalytic activities.2O NCs followed the sequence of octahedra > cubooctahedra > cubes. The exposed {111} facets of o‐Cu2O had positively charged “Cu” atoms that inclined to interact with the negatively charged groups –SO3− in MO molecules. This suggested that Cu2O {111} facets would strongly interact with the molecules possessing negatively charged groups, and then effectively photodecompose these molecules; while the {111} facets interact weakly with the positively charged molecules, and lead to a poor photodegradation activities. As expected, M. H. Huang et al.o‐Cu2O was higher than that of c‐Cu2O. Furthermore, the photocatalytic activities of extended hexapods Cu2O NCs with more {111} facets were more effective and active than o‐Cu2O  pair separation would contribute to the improvement of photocatalytic activity. Besides the strong interaction between MO and the {111} corners and {110} edges of Cu2O jagged polyhedron  heterostructure, and demonstrated that the synergistic effect between charge spatial separation and Schottky barrier contributed to the efficient hydrogen production from pure water . CuO/c‐Cu2O became active at 190 ºC and achieved a conversion rate of 49.1% CO at 240 ºC, while CuO/o‐Cu2O became active at 140 ºC and achieved the conversion rate of 93.2% CO at 240 ºC  and three‐coordinated Cu (Cu3c) atoms were terminated at the CuO overlayer on {111} facet  surface intermediate (SI) was formed. Subsequently, the OCOO(a) SI disintegrated into CO2 and a O(a) adatom, with an activation energy (aE) of 0.37 eV. Finally, CO reacted with O(a) adatom to produce CO2 with a aE of 0.17 eV; thus, a cycle of catalytic process has completed. For the surface of CuO/c‐Cu2O  SI was formed. Next, the CO3(a) SI disintegrated to generate CO2, and an oxygen vacancy (OV) was created in CuO with a aE of 1.15 eV. Subsequently, O2 molecules could adsorb on OV in CuO to produce O2(a). Finally, CO reacted with O2(a) to produce CO2 with a aE of 0.67 eV; thus, a cycle of catalytic process has completed, and the OV has refilled. Therefore, DFT calculation results were in accordance with experimental results, which demonstrated that CO oxidation catalyzed by CuO/o‐Cu2O proceeded with a lower aE (the disintegration of the OCOO(a), 0.37 eV) than that catalyzed by CuO/c‐Cu2O (the disintegration of the CO3(a) SI, 1.15 eV).Further DFT calculation results demonstrated that there were significant differences in the reaction process and active sites during the process of CuO/O Figure g,h. For O Figure g, indiviO Figure h, O2 molc‐Cu2O, o‐Cu2O, and d‐Cu2O. c‐Cu2O enclosed by {100} facets were most selective for CO2; o‐Cu2O exposed {111} facets were most selective for acrolein; d‐Cu2O enclosed by {110} facets were most selective for propylene oxide  plane was terminated with three‐coordinated unsaturated O (OCUS) in the first layer, and one‐coordinated unsaturated Cu (CuCUS) and coordinated saturated (CuCSA ) in the second layer in a 1:3 ratio. The (100) plane was terminated with two‐coordinated OCUS in the first layer, and CuCSA in the second layer. The (110) plane was terminated with three‐coordinated OCUS and CuCSA in the first layer, and CuCSA in the second layer. DFT calculations explained the adsorption of C3H6 on (111), (100), and (110) facets  was formed through the selective adsorption of C3H6 molecules at the site of CuCUS (C=C stretching frequency  of 1560 cm−1) with an adsorption energy (adsE) of –1.53 eV. For the (100) facet  was formed through the selective adsorption of C3H6 molecules at the site of two neighboring two‐coordinated OCUS ( = 1453 cm−1) with an adsE of –2.85 eV. For the (110) facet  ( = 1437 cm−1), and on OCUS site to generate OCUS–C3H6(a) ( = 1574 cm−1). The adsE for the two sites of (110) facet was similar.W. X. Huang et al.de Figure17a. Al2O NCs. On the Cu2O (111) surface, the distance of C=C bond (dC=C) in CuCUS–C3H6(a) was calculated to be 1.37 Å, while dC=C in C3H6 molecule was 1.34 Å. Therefore, the stable C=C bond of CuCUS–C3H6(a) can be kept in the subsequent reactions, which was in favor of the generation of acrolein. On the Cu2O(100) surface, dC=C in OCUS,OCUS–C3H6(a) was 1.59 Å; hence, the weakened C=C bond would be cleaved by propylene combusting. DFT calculation results  to adsorb C3H6O(a) and the disintegration of OCUS, OCUS–C3H6(a) into adsorbed CH2(a) and CHCH3(a) was 2.09 and 1.02 eV, respectively. This result suggested that propylene was in favor of combustion, which was in accordance with the experiments of c‐Cu2O. On the Cu2O(110) surface, dC=C in OCUA–C3H6(a) was 1.36 Å, which was considered to the generation of acrolein; while the weakened C=C bond in CuCSA,OCUS–C3H6(a) with a distance of 1.50 Å inclined to break during the reactions. DFT calculations results  to adsorb C3H6O(a) and the disintegration of OCUA,OCUS–C3H6(a) into adsorbed CH2(a) and CHCH3(a) was 1.28 and 2.08 eV, respectively. This result suggested that propylene was in favor of epoxidation, which was in accordance with the experiments of d‐Cu2O. The distinction in reactivities between CuCSA,OCUS–C3H6(a) on Cu2O(110) and OCUS,OCUS–C3H6(a) on Cu2O(100) is three‐coordinated OCUS on (110) facet and two‐coordinated OCUS on (100) facet. Three‐coordinated OCUS is less electrophilic than two‐coordinated OCUS, which is to the disadvantage of the breakage of the C=C bond in propylene.In addition, different SI produced on each Cu=C bond dC=C in Cus Figure b suggest2O polyhedra. Due to the presence of high‐index {311} planes on their surfaces, the 50‐facet Cu2O microcrystal showed the highest specific catalytic rate (8.8 × 10−6 mol m−2cat s−1), which was markedly higher than d‐Cu2O, o‐Cu2O, c‐Cu2O and rhombicuboctahedron  has been reported as excellent catalysts for cross‐coupling reactions.c‐Cu2O, o‐Cu2O, and d‐Cu2O NCs was firstly evaluated by M. H. Huang et al.2O NCs, all the three NCs were used with identical surface area  commercialized or in the stage of development, have aromatic C—N and aromatic C—C bonds that can be coupled by organocatalysts through cross‐coupling reactions.rea Table1. d‐Cuc‐Cu2O, d‐Cu2O, and octadecahedra to catalyse aerobic oxidative coupling of phenylacetylene and arylboronic acids. During the catalytic reaction, those NCs showed high yields but different crystal surface stability. After three catalytic cycles, c‐Cu2O were seriously etched and aggregated beyond recognition, as well as their yield dropping from 94% to 32%. By contrast, no change was observed in the {110} facets of d‐Cu2O and octadecahedra during the reaction. Interestingly, Cu2O octadecahedra had the best catalytic activity upon recycling, and the yield of aerobic oxidative coupling was increased from 89% to 97%. The reason was that the {100} facets of Cu2O octadecahedra were more prone to etching than the {110} facets during this catalytic reaction, and the Cu2O octadecahedra were gradually oxidized and etched to high‐active concaves  and disassembled nanocubes (≈20 nm), and the corresponding TEM images were shown in Figure2O illustrated a better sensing capability than the disassembled Cu2O  composite mesocrystals. The obtained mesocrystals with marked octahedral shape and eight {111} facets were composed of highly oriented nanowires. They further compared the NO2 sensing performance of Cu2O NW, rGO and rGO–Cu2O mesocrystals at room temperature. In the presence of NO2, all the three samples exhibited an increased sensitivity with the increasing concentration of NO2  were calculated as 64, 81, and 82 ppb for rGO–Cu2O, Cu2O NW, and rGO, respectively. The improved sensing performance of the rGO–Cu2O mesocrystals was attributed to their high specific surface area and enhanced conductivity. When rGO–Cu2O was exposed to NO2, the NO2 molecule could obtain e− from the “activated” surface O ion, and the rGO with excellent electrical conductivity could effectively transfer electrons that promoted the h+ conductivity in the Cu2O . At –0.65 V, all three samples illustrated sharp stripping peaks of Pb2+ with different detection limit and sensitivity   on {100}, {110} and {111} facets were calculated as 4.952, 4.761 and 5.742 eV, respectively. These calculated results demonstrate the stronger Pb2+ adsorption ability of {111} facet, followed by the {100} and {110} facet, which agreed quite well with the electrochemical performance.DFT calculations were employed to investigate the adsorption mechanism of Pb) Figure b1, one Oe Figure b2, two O72O‐based NCs with heterogeneous, etched, or hollow structures. These routes depend on the different surface atomic structure of Cu2O NCs, in which the selective adsorption of CAs could protect special facets, and the surface energy and active sites would determine the reaction activity trend. The facet‐dependent properties of the Cu2O NCs and such Cu2O‐based NCs have been investigated, especially in the realm of photocatalysis, gas catalysis, organocatalysis and sensing. Due to different crystal surface structures, the Cu2O NCs exhibit distinct facet‐dependent properties; a subsequently rational design and synthesis of Cu2O‐based NCs could tailor and optimize their facet‐dependent performances. Although the controllable synthesis of NCs and their derivatives has seen considerable progress and development in the last decade, the next requirements for NCs with excellent performance are the development of more simple and convenient synthetic routes to tailor NCs with ideal components and structures.Through numerous examples, we have demonstrated that facet‐controlled synthetic strategies provide remarkably facile and convenient approaches to the preparation of CuThe progress we have summarized also opens the door for in‐detail studies in catalysis and sensing. Due to their well‐defined facets, shape‐controlled NCs can provide smooth surfaces for further delicate carving, modifying, or transforming; a deep insight into the relationship between structures and properties will be obtained by combining with theoretical calculations and simulations of the catalysis and sensing process. This perception will enable further delicate tailoring of NCs, and bridge the gap between structures and properties, so that traditional trial‐and‐error pattern to obtain functional NCs would be instead replaced by ingenious design and controllable synthesis.2O‐based NCs could also apply to other realms. For instance, our groupo‐Cu2O NCs displayed a higher oxidative stress to D. magna than that of c‐Cu2O due to its higher reactivity. M. H. Huang et al.2O NCs. o‐Cu2O is highly conductive, c‐Cu2O is moderately conductive, and d‐Cu2O is nonconductive. A thin surface layer having different degrees of band bending contributed to the different conductivities. Interestingly, a diode‐like response was obtained when electrical connection was made on two different facets of a rhombicuboctahedron. D. F. Xue et al.c‐Cu2O had the highest capacity among Cu2O polyhedra (the sequence of electroactivity is {110} < {111} < {100}), because {100} facets had high electroactivities toward redox reactions. Thus, more instances of the facet‐dependent properties should be continuously explored, endowing nanomaterials with excellent performances for numerous applications.Finally, it is should be envisaged that the facet‐dependent properties of Cu


Benefiting from the unique nanoarchitecture, high MoS2 loading (90.3 wt%) and the expanded interlayer spacing, the as-prepared MoS2@rGO nanoflakes exhibit greatly enhanced sodium storage performances including a high reversible specific capacity of 441 mAh g−1 at a current density of 0.2 A g−1, high rate capability, and excellent capacity retention of 93.2% after 300 cycles.A simple one-pot hydrothermal method is developed for fabrication of MoS Na and Li elements share many similar physical and chemical properties, which makes the strategies applied in lithium ion batteries (LIBs) valuable references to develop SIBs9. However, the large radius of Na ion and sluggish transport kinetics limit the stability and rate performance in most electrode materials and thus hinder the development of SIBs14.Rechargeable sodium ion batteries (SIBs) are seen as promising options for large scale energy storage systems because of the natural abundance of sodium and lower production cost2), with a well-defined lamellar structure similar to graphite, has been actively studied as anode material for both LIBs and SIBs20. Although the discharge  potential is slightly higher than other anode materials like carbon and metal oxides, MoS2 is particularly attractive as a high capacity sodium host , due to its dichalcogenide structure and large interlayer spacing. However, because of its high surface energy and interlayer van der Waals attractions, the two-dimensional (2D) layered structure is thermally unstable, and has a trend to restack irreversibly during the cycling process, leading rapid capacity fading and poor rate performance24. This phenomenon is especially severe in Na+ storage because Na ions are about 55% larger in radius than Li ions11. Previous studies have revealed that when MoS2 is cycled to very low potential (0 V versus Na/Na+) to achieve high capacity for SIBs, Mo metal nanoparticles are formed within a Na2S matrix, and subsequent electrochemical cycling operates as a sodium–sulfur redox couple. It indicates that the parent crystalline atomic structure of MoS2 is completely destroyed and does not reform after the Na is removed, resulting in poor cycling stability especially at high rates27. Cycled in a limited voltage region (between 0.5–2.6 V versus Na/Na+) without destroying the 2D atomic layered structure of MoS2 has been proved to be an effective way to improve the cyclability, but the achieved capacity is much lower than the target29.Molybdenum disulfide 29. Su et al. reported an ultrathin MoS2 exfoliated nanosheets, which exhibited a high initial discharge capacity of 998 mAh g−1 while after 100 cycles the remained discharge capacity is just 386 mAh g−110. The cycle stability of nanoarchitecture MoS2 is still far from an ideal and exhibits an obvious capacity decay from the very beginning. The poor performance may be attributed to the large volume change during cycle which tends to severely damage the carefully designed nanostructure. Incorporating with carbonaceous materials  is another effective approach. Graphene oxide (GO) with a well-defined lamellar structure similarity to MoS2 may sever as an excellent carbon host to modify structural stability, improve the electronic conductivity and trigger enhanced reaction kinetics of MoS2. Qin et al. prepared MoS2-reduced graphene oxide (rGO) composites via a facile microwave assisted method, achieving a stable reversible capacity of 305 mAh g−1 at 100 mA g−1. However, the remained capacity was only 218 mAh g−1 after 50 cycles31. Xie et al. prepared MoS2/rGO nanocomposites with intimate two-dimensional heterointerfaces by hydrothermal method, the composite exhibits much higher initial capacity of 702 mAh g−1 at a current density of 20 mA g−1, but the capacity retention is only 49% after 100 cycles21. It is assumed that a suitable rGO host can optimize the electrochemical performance by improve the electron and ion transfer ability of the composite and buffer the large volume change during cycle, but in most cases the synthesis processes are relatively complicated and the molybdenum sources are rather expensive. Therefore, it is desirable to develop a MoS2 anode with both high capacity and long cycle life in an economical way.To enhance the structure stability of MoS2@rGO composites using an economical molybdenum source of MoO3. By controlling the concentration of aqueous rGO solution in hydrothermal treatment and engineering the ionic strength of precursors, three-dimensional (3D) architectures constructed of MoS2/rGO nanoflake is developed. The prepared MoS2@rGO composites with high loading of MoS2 exhibit excellent cycle stability and rate performance, making the synthesized MoS2@rGO a promising anode material for SIBs.Herein, we report a facile one-pot hydrothermal strategy to prepare the MoS2 and MoS2@rGO composites . As shown in Fig. 2 (JCPDS 37–1492), demonstrating that MoS2 is successfully synthesized. Compared to the pristine MoS2, the MoS2@rGO composites exhibit broadened and less prominent peaks at (002) and (103), suggesting the formation of smaller MoS2 crystallite. In addition, the interlayer spacing  of the MoS2@rGO composites is calculated to be 0.64 nm, which is larger than that of the pristine MoS2 (0.61 nm), implying the expansion in the (002) interlayer of MoS2. The expanded interlayer of MoS2 can lower the energy barrier of Na+ intercalation and facilitate Na+ diffusion33. Meanwhile, the (002) characteristic broad peak of rGO at about 26° is not observed in the MoS2@rGO composites, suggesting the fine distribution and exfoliation of rGO sheets which is beneficial for electronic conducting and high mass loading of MoS2. X-ray photoelectron spectroscopy (XPS) measurements are conducted to analyze the composition and chemical states of MoS2@rGO composites. The two peaks at 233.0 and 229.9 eV in the inset graph of Fig. 3/2 and Mo 3d5/2 of Mo4+. The spectra of S 2p in Fig. 1/2 and S 2p3/2, indicating the valence of S is −2. In the meantime, the C1s peak appearing at 285.0 eV  vibrations, respectively, indicating the few stack layered structure of MoS2 in rGO36. The Raman spectra of different MoS2@rGO composites are shown in Fig. 2@rGO-1), 1.42 (MoS2@rGO-2) and 1.43 (MoS2@rGO-3). As is known, the intensity ratio between D band and G band (ID/IG) is an important parameter to evaluate the rGO composites, the higher the ID/IG ratio, the stronger the disorder degree will be. For electrode materials, a higher ID/IG ratio is beneficial for electronic conducting and electrolyte penetration.X-ray diffraction spectrometry (XRD) is used to investigate the crystalline phases of the as prepared MoS eV Fig.  is relat2 loading and surface area of the MoS2@rGO composites are characterized by the TGA measurement and N2 adsorption/desorption isotherm analysis, respectively, which are summarized in Table 2 in the composites are determined to be 94.7 wt% (MoS2@rGO-1), 90.3 wt% (MoS2@rGO-2), and 81.4 wt% (MoS2@rGO-3). Corresponding thermogravimetric curves of MoS2@rGO composites are shown in Fig. 2 possess a relative small BET specific surface area of 8.6 m² g−1. When compositing with rGO (BET specific surface area is 106.3 m² g−1), the BET surface area of the composites increase to 18.9 m² g−1 (MoS2@rGO-1), 26.3 m² g−1 (MoS2@rGO-2), and 37.2 m² g−1 (MoS2@rGO-3). The increased BET surface area may modify the electrode-electrolyte interface and provides fast Na ion diffusion channel. However, the specific capacity of composites may decrease because rGO serves merely as a buffer and conductive skeleton rather than the accommodation of Na ion. Raising the proportion of rGO in the composite is beneficial for the enhanced conductivity but unfavorable for the specific capacity.The MoS2 and the MoS2@rGO composites are further observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM images of products obtained with different concentration of rGO solution are also shown in Fig. 2 in Fig. 2, hollow spherical structure is effectively inhibited and composite with nanoflake morphology is shown . In the meantime, NH2CSNH2 is hydrolyzed to form H2S (CS(NH2)2 + 2H2O → CO2 + 2NH3 + H2S). Then, surface MoO2 reacts with H2S to form MoS2 shell outside the MoO2-MoO3 which serves as the moving boundary in the subsequent reaction. At the last, inner MoO3 is reduced to MoO2 then react with HCl to form Mo4+, which transfer along the formed MoS2 boundary and reacting with H2S to form MoS2 hollow spherical eventually. For MoS2@rGO composite, the addition of positive-charged NH4+ could screen the electrostatic repulsion of GO colloids and the MoO3 powders can be uniformly adsorbed onto GO sheets. Owing to the oxygenated functional groups acted as nucleation sites, the MoS2 grows gradually perpendicular to the GO skeleton surface and forms nanoflakes as the gradual reaction proceeding during hydrothermal treatment. The unique vertical aligned MoS2 nanoflake could maximize the MoS2 loading in composites (90.3 wt%) which is much higher than those shown in previous reports.The dramatically different microstructures of the pristine MoS2 and MoS2@rGO composite are characterized by CV and galvanostatic charge-discharge cycling. Figure 2@rGO composite in the range of 0–3 V vs. Na+/Na at a scan rate of 0.1 mV s−1. In the first cycle, three reduction peaks in the sodiation process are observed. The reduction peak at 0.81 Vs. Na+/Na is assigned to the Na+ insertion into MoS2 to form NaxMoS2 (x < 2). The following reduction peak at 0.53 V vs. Na+/Na is attributed to the further insertion of Na+ and at the same time with the formation of solid electrolyte interphase (SEI) layer. The broad peak at 0.1 V vs. Na+/Na is related to the conversion of MoS2 to form metallic (Mo) embedded in an amorphous Na2S matrix. A broad anodic peak observed in the first charging process at about 1.8 V corresponds to the oxidation of the Mo and Na2S to MoS2. In brief, the sodiation/desodiation of the MoS2@rGO composites appears to be based on a two-step reaction process, including an initial insertion process described by MoS2 + xNa ↔ NaxMoS2 (x < 2) and the following conversion reaction that MoS2 converts into Mo and Na2S described by NaxMoS2 + (4 − x) Na ↔ Mo + 2Na2S. The CV curves exhibit no significant variation during the following three cycles, demonstrating the high stability and reversibility of the electrode. The ex-situ XRD result . MoS2@rGO-2 reveals the largest reversible specific discharge capacity. The coulombic efficiency of MoS2@rGO composites rise up to 99% rapidly in the initial few cycles  measurements. The Nyquist plots of the MoS2 and MoS2@rGO nanoflakes after different cycles (30th and 50th) are displayed in Fig. RSEI) and charge transfer resistance (Rct) of the pristine MoS2 increase dramatically during cycling, implying the poor structural stability and sluggish kinetics. For the MoS2@rGO nanoflakes, RS and Rct are much smaller than that of the MoS2, and keep almost constant during cycling, indicating a thinner and more stable SEI film favoring rapid Na+ insertion/extraction and fast charge transfer at the electrode/electrolyte interface, which in part explains the high discharge capacity and good rate capability of MoS2@rGO nanoflakes that have been observed.Furthermore, the MoS2@rGO composites as anode materials in SIBs were synthesized via a facile hydrothermal method. Owing to the oxygen functional groups of rGO acted as the nucleation sites, few-layered MoS2 nanoflakes are vertically grown and embedded in the rGO nanosheets, which exhibits high specific capacity, outstanding cycle stability and rate capability. The greatly enhanced electrochemical performance of the MoS2@rGO nanoflakes can be mainly attributed to the synergistic effect of its unique structural features and high loading of active materials, which not only enhances the electrical conductivity and create more electrochemically active sites, but also alleviate the huge inherent volume change of MoS2. Furthermore, the expanded interlayer distance of the MoS2 nanosheets benefits fast ion intercalation and provides structural stability, leading to high rate capability and long term cyclability. In addition, this synthesis route with the economical metal oxides as the sources of metal elements may be suitable for the fabrication of other high-loading metal sulfides@rGO composites with outstanding performance in SIBs.In summary, the ultra-stable MoS37. MoS2@rGO is synthesized by hydrothermal method as follows: 1.0 g MoO3, 1.5 g thiocarbamide and 1.5 g NH4OHCl were uniformly mixed in 40 ml of DI water via vigorous magnetic stirring. 40 ml of GO suspensions with different concentrations  were added to the precursor suspension dropwise and kept stirring vigorously for 20 min. The precursor was then transferred to an autoclave and subjected to a hydrothermal treatment at 180 °C for 48 h. The resultant was rinsed with DI water and ethanol repeatedly via filtration. The precipitate was dried in a vacuum oven at 80 °C overnight. Finally, the as-synthesized samples were annealed at 600 °C for 5 h in a N2 atmosphere to reduce the oxygen functional groups of GO and improve the crystallinity of MoS2 at the same time. The composites with different weight ratios of MoS2 are named as MoS2@rGO-1,2,3. The pristine MoS2 was synthesized following the same hydrothermal route for comparison.GO was synthesized in a modified Hummer’s method using the commercial graphite as the original materialλ = 1.5406 Å) was used to characterize the crystalline structure and interlayer spacing of MoS2 in the 2θ range of 10–80°. The weight ratios of MoS2 in composites were measured by the thermal gravity analysis  in the atmosphere of nitrogen and oxygen (80:20) at a heating rate of 10 °C min−1 in the temperature range of 30–600 °C. The N2 adsorption-desorption isotherms were measured using an adsorption unit  to evaluate the Brunauer-Emmett-Teller (BET) surface area and pore size distribution. Prior to measurement, samples were degassed in a vacuum of 10−6 Torr at 150 °C for 12 h to remove the adsorbed moisture. X-ray photoelectron spectroscopy  measurements were performed to analyze the element valence states of MoS2@rGO composites with a monochromatic Al-Kα X-ray source. Raman spectra were recorded on a Renishaw Invia spectrometer using Ar+ laser of 514.5 nm.The morphology of the prepared composites was characterized by field-emission scanning electron microscopy  and high-resolution transmission electron microscopy . X-ray diffraction  equipped with a Cu-Kα1 radiation  were mixed in a mortar at the weight ratio of 8:1:1 to form a homogenous paste and casted on the copper foil. The loading density of the active material was maintained at approximately 1.2 mg cm−2. The electrode was dried in a vacuum oven at 120 °C for 12 h. The electrolyte was anhydrous solution of 1 M NaPF6 in ethylene carbonate and diethyl carbonate (1:1 in volume ratio). The sodium metal film was used as the counter electrode and the Celgard 2400 was used as the separator. The coin cells (CR2032) were assembled in an argon-filled glove box with the oxygen and moisture levels being less than 0.1 ppm. The galvanostatic charge-discharge tests  were tested in the potential range of 0.01–3.0 V at 25 °C. Cyclic voltammetry (CV) tests were performed at a scan rate of 0.1 mV s−1 in the voltage range of 0.01–3.0 V. Electrochemical impedance spectroscopy (EIS) measurements were performed at an AC amplitude of 5 mV in the frequency range of 105–10−2 Hz.The MoSSupplementary Information


While many studies have been done on the mutual toxicity of Cd2+ and Zn2+, few studies can be found in the literature focused on the interaction of Cd2+ and Zn2+ on soil clay fractions especially in terms of energy relationship.The coexistence of Cd2+ on boggy soil (Histosols) particles and Zn2+ on yellow brown soil (Haplic Luvisols) particles were the highest, while those of Cd2+ and Zn2+ on paddy soil (Inceptisols) particles were the lowest. These results indicated that Cd2+ and Zn2+ have a strong capacity to adsorb in the solid phase at the soil–water interface of boggy soil and yellow brown soil, respectively. However, both Cd2+ and Zn2+ adsorbed on paddy soil particles easily release into the solution of the soil suspension. Unlike the binding energy, the higher adsorption energies of ions in boggy and yellow brown soils showed a weak binding force of ions in boggy soil and yellow brown soil. A 1:1 ratio of Cd2+ to Zn2+ promotes the mutual inhibition of their retentions. Cd2+ and Zn2+ have high mobility and bioavailability in paddy soil and yellow drab soil , whereas they have high potential mobility and bioavailability in boggy soil and yellow brown soil.The binding energies of Cd2+ had preferential adsorption than Cd2+ on soil clay fractions. Boggy soil and yellow brown soil have a low environmental risk with lower mobility and bioavailability of Cd2+ and Zn2+ while paddy soil and yellow drab soil present a substantial environmental risk. In the combined system, Cd2+ and Zn2+ restrain each other, resulting in the weaker binding force between ions and soil particles at a 1:1 ratio of Cd2+–Zn2+.In the combined system, Zn In China, about 13% of soils included in the national assessment of soil contamination hold excessive amounts of inorganic pollutants  or in se2+ and Zn2+. Turner , 1:1 Cd:Zn [0.10 mol L−1 Cd(NO3)2 and 0.10 mol L−1 Zn(NO3)2], and 1:3 Cd:Zn [0.05 mol L−1 Cd(NO3)2 and 0.15 mol L−1 Zn(NO3)2]. The surfaces of the clay fraction particles were saturated with Cd2+ and Zn2+ through three successive batches that included agitation, centrifugation, supernatant disposal and resuspension in the initial solution. Thereafter, the non-adsorbed ions were removed from particle surfaces through successive batches with deionized water that were repeated until the EC stabilization of the supernatants in a minimal value. The saturated particles were then oven-dried, ground, sieved and analyzed for their total amounts of Cd and Zn in an atomic absorption spectrophotometer Hitachi 2000 after microwave-assisted acid dissolution [−1) of the saturated particles were prepared in 50-mL centrifuge tubes, agitated for 30 min and then sonicated for 45 min. After 10 additional 1-h agitations intercalated with 23 h of standing, the equilibrated suspensions were used in the measurements of the Wien effect for assessing binding energies of Cd and Zn cations adsorbed to the soil clay fractions.The soil clay fractions were suspended in solutions containing 0.4 mol Lsolution . AqueousThe electrical conductivity under strong electrical fields was measured with the SHP-2 (short high-voltage pulse) apparatus. Both the SHP-2 apparatus features and the measuring procedure were detailed elsewhere , 27, 33.0 is proportional to its concentration in the equilibrium solution. Then, the following equations can be considered:i0 and ECj0 are the respective weak-field electrical conductivities caused by cations i and j (mS cm−1); Ci and Cj are the respective concentrations of cations i and j in the equilibrium solution (mol L−1); λi and λj are the respective equivalent conductivities of cations i and j (mS L cm−1 mol−1); and EC0 is the weak-field electrical conductivity associated with the Wien effect (mS cm−1).The direct relationship between ion activity and electrical conductivity was considered for the evaluation of both mean Gibbs free binding and adsorption energies. The evaluation of the mean Gibbs free binding energies in samples saturated with two metals is based on the assumption that the cation contribution to ECbi) is calculated with the following equation:−1 K−1); T is the temperature (K); Mi is the adsorbed amount of cation i (mol kg−1); Dp is the suspension particle density (g L−1); λi is the equivalent conductivity of the cation i (mS L cm−1 mol−1); and ECi0 is the weak-field electrical conductivity caused by cation i.The mean Gibbs free binding energy of each cation   2) of thEquation  enables 2+ and Zn2+ on clay particles and in equilibrium solutions as well as their distribution coefficients are shown in Table 2+ and Zn2+ on the clay-sized particles ranged from 122.1 to 173.3 mmol kg−1 and conformed to the CEC values determined for the whole soil samples. The Cd2+ to Zn2+ ratios in the clay-sized particles also agreed with the expected ones. The total cation concentrations in equilibrium solutions ranged from 0.008 to 0.170 mmol L−1.The amounts of Cd0) is proportional to the concentration of dissolved ions found in solution. Most of EC0 values of the suspensions containing clay-sized particles extracted from the paddy soil (Inceptisols) and yellow drab soils  were the highest measured ones   and the smallest one verified in the paddy soil. Likewise, the binding energies of Zn2+ ranged from 5.7 to 7.2 kJ mol−1, with the largest one for the yellow brown soil (Haplic Luvisols) and smallest one for the paddy soil. As Table In all soils, the binding energies of Cd−1) Fig. , which w2+ and Zn2+ in the mono-metal systems were higher than those in the competitive systems. Shaheen et al. [2+ and Zn2+ in the competitive systems. Furthermore, the Cd2+ binding energy was lower in the competitive system while that of Zn2+ had no significant reduction compared to that observed in the single system. Antoniadis and Tsadilas [2+ and soil particles was smaller and prone to be affected by competitive ions.The binding energies of Cdn et al. , 36 obseTsadilas  also obt2+ and Zn2+, respectively, while paddy soil has lower affinity for both cations. In other words, boggy soil and yellow brown soil attracted Cd2+ and Zn2+, respectively. On the other hand, both Cd2+ and Zn2+ tend to escape from the particles of paddy soil into soil solution.Boggy soil and yellow brown soil showed higher affinities for Cd2+ and Zn2+. Thereinto, soil organic matter has higher affinity for Cd2+ at lower pH, while clay minerals and Fe/Al oxides have stronger affinities for Zn2+ than Cd2+ at higher pH and lower surface coverage [2+ and Zn2+ were 4.49 and 5.31. Therefore, soil organic matter may be the crucial factor affecting the binding energies of Cd2+ and Zn2+ on various soil clay fractions. As Table 2+ or Zn2+ in the combined system with different Cd:Zn molar ratios and the DOC contents in soil clay fractions was analyzed and shown in Fig. 2+ or Zn2+ is. The presence of dissolved organic matter (DOM) enhances the solubility of metal ions in soil–water system by forming the soluble DOM-metal complex [2+ to Zn2+ affects the partition of metal ions on the interface of soil–water. In addition, the binding energies of Cd2+ and Zn2+ all decreased with increasing the proportion of metal ions in soil particles, which is consistent with what Tiller et al. observed [Soil is a multi-component system comprised of clay minerals, organic matter and Fe/Al oxides. These components have different selectivity towards Cdcoverage . The pHs complex , 17. The complex , while t complex , 41. Theobserved .Fig. 4Th−1, while the growth of adsorption energies was rapid at high field strength (E > 100 kV cm−1). However, the adsorption energies decreased on the order of 1:1 > 1:3 > 3:1 of Cd2+:Zn2+ ratio in different soil particles with an increase of the field strength above 100 kV cm−1. At a Cd2+:Zn2+ ratio of 1:1, the adsorbing strength of electrically bound ions to soil particles was weak, thus leading to detachment of more ions from soil particles under application of electrical field. In addition, more ions were easier to desorb in the combined system with 75% Zn2+ and 25% Cd2+, compared with the system with 25% Zn2+ and 75% Cd2+, at the same field strength. This suggests that the binding of Cd2+ with soil particles is tighter than Zn2+, which is consistent with the order of electronegativity of Cd2+ (1.7) and Zn2+ (1.6) [2+ > Zn2+ in accordance with the electronegativity of trace metal. Also, Moreira and Alleoni [2+ and Zn2+ retention in soils. Consequently, the binding strength for Cd2+ adsorbed on soil particles is stronger than that for Zn2+ in view of the electronegativities of Cd and Zn. In addition, the Misono softness parameter calculated from ionic radius and ionization potential is also used to predict the tendency of metals to form complexes. The ability to form strong complexes for Cd2+ is stronger than for Zn2+, depending on the parameter [The adsorption energies of metal ions on soil particles as a function of applied field strength were evaluated according to the calculation method proposed by previous studies. An indication of electrically adsorbing strength was used to identify the detachment tendency of ions from soil particles by external force provided by the applied electrical field. The greater the adsorption energy is, the weaker is the electrically adsorbing strength of metal ions on the surfaces of soil particles. As Fig. 2+ (1.6) , 43. As 2+ (1.6)  predicte Alleoni  proposedarameter .Fig. 5Me−1 (Table −1)  Table  at 200 k2+–Zn2+ binary systems at various ratios of Cd2+ to Zn2+. The binding energy and adsorption energy spectra of Cd2+ and Zn2+ for the soil clay fraction particles were calculated based on the EC-E curves. Compared to the binding energies of Cd2+ and Zn2+ in the mono-metal system, more Zn2+ was electrostatically adsorbed on the clay fraction particles of the four studied soils than Cd2+. The binding energy results in the competitive system suggested that Cd2+ is inclined to combine with the clay fraction particles of boggy soil and Zn2+ tend to combine with clay fraction particles of yellow brown soil. For paddy soil, Zn2+ and Cd2+ are prone to partition into soil solution, resulting in the increase of the mobility and bioavailability of metal ions. Although soil clay fraction particles have a strong attraction to certain ions, the binding force between ions and soil particles may be weak. The adsorption energies of ions in boggy soil and yellow brown soil were higher, indicating weaker electrically adsorbing strength between ions and soil particles. Consequently, mobility and bioavailability of Cd2+ and Zn2+ are poor in boggy soil and yellow brown soil, respectively, while the potential mobility and bioavailability of Cd2+ and Zn2+ are high with the external force provided by the applied electrical field. In the combined system there was antagonism between Cd2+ and Zn2+ resulting in a weaker binding force between ions and soil particles at a 1:1 ratio of Cd2+–Zn2+. Furthermore, the affinity of ions to soil particles decreased with the increase of the proportion of ions (Cd2+ or Zn2+) in the Cd2+–Zn2+ binary samples.Soil heavy metal contamination is not only single-metal ion contamination but also a binary pollution. In this study, the suspension Wien effect was used to investigate the interactions between two species of heavy metal ions and four types of soil clay fraction particles in the Cd


Below 2000 K the most thermodynamic stable matter is CeO2 and the less thermodynamic stable inclusion is CeS. Only when the amount of [O] is extremely low and the amount of [S] and [Ce] is relatively high, Ce2S3 has the possibility to form.Thermodynamic calculation has been applied to predict the inclusion formation in molten SS400 steel. When the Cerium addition in liquid iron is 70 ppm and the initial Oxygen and Sulphur are both 110 ppm, the formation of oxides containing Cerium would experience the transformation from Ce Rare earth (RE) metals have many applications123411121516172S3, Ce3S4, CeO2, and Ce2O3 in molten steel are examined using Wagner’s relation and Lupis’s relation based on the Gibbs free energy change. The transformation mechanism is analyzed by determining the thermodynamic conditions of Ce-desulfurized and Ce-deoxidized steel. The segregation of Ce2O3 in molten iron is also analyzed. In addition, a model for predicting the formation of various inclusions is established for SS400 steel with cerium addition.This paper focuses on the thermodynamic calculations of the cerium-oxygen-sulfur system in molten SS400 steel. The formation conditions of CeS, Ce2O3 in molten SS400 steel, whose chemical composition is shown in The thermodynamic calculations of the Ce-O-S system are based on Wagner’s relationThe Ce-O-S system is the thermodynamic relation between the dissolved Oxygen, Sulphur and Cerium in liquid iron to explore the formations of inclusions containing Cerium. The first stage for thermodynamic calculation is to derive the thermodynamic equations for the inclusion formations by Wagner’s relationw(RE)/(w[O] + w[S]) = 3.9, the function of cerium is optimal. To determine the separation sequence for various oxides and sulfides of cerium, the amount of cerium in the calculations was set as 1 mol to compare the Gibbs free energy of formation for various inclusions, which can be derived as:For the addition of cerium into molten SS400 steel, the reactions of [O], [S], and [Ce] are of interest because Ce has strong affinity with S and O. As reported previouslyJ denotes the reaction quotient (unitless), ∆G is the Gibbs free energy change of reaction (J/mol), ∆Gθ denotes the Gibbs free energy change of reaction for unmixed reactants and products at standard conditions (J/mol), R is the gas constant (J·mol−1·K−1), T is temperature (K), and K is the equilibrium constant (unitless).where The Gibbs free energy of oxides, sulfides and oxysulfides of cerium are shown in 1421222324252, as shown in 2 likely formed in the molten iron when the temperature reached the simulated steelmaking temperature of 1873 K. In 2 > Ce2O3 > Ce2O2S > Ce2S3 > Ce3S4 > CeS. However, the most thermodynamically stable matter does not guarantee the formation of CeO2, because the formation of oxides containing cerium are controlled not only by the equilibrium constant but also by the concentrations of cerium and oxygen in the molten iron. That is to say, the formation of CeO2 at 1873 K is also determined by the solubility product of CeO2 and the concentration of cerium and oxygen, even though the Gibbs Free Energy of CeO2 is the lowest at 1873 K.Below 2000 K, the most thermodynamically stable inclusion was CeOThe activities and activity coefficient of Ce, O and S can be written as fi is the Henrian activity coefficient of component i relative to the dilute solution and i on j in molten iron; w[i] and w[ j] are the mass percentages of elements i and j, respectively ( and WO) and kO (=0.022) are the solvent partition coefficients at equilibrium for cerium and oxygen, respectively; fs is the solid fraction.where 2O3 formed in molten iron can be expressed as:The solidus temperature of SS400 is 1777 K. The solubility product of the Ce2O3 formed in molten iron at equilibrium can be expressed as:The solubility product of the Ces) are plotted in s) are plotted with the varying cerium concentration (shown in the colorful lines of 2O3 (KCe2O3) versus solidification ratio fs is curved as the black solid line in 2O3 prefers to segregate in liquid phase with the 10 ppm Oxygen concentration in liquid iron. Moreover, the same conclusion can be drawn from the similar 2O3 preferred to segregate in the liquid phase.From 2O3 to CeO2 and also the formation of sulfides containing Cerium would experience the transformation from CeS to Ce2S3 and then to Ce3S4. Below 2000 K the most thermodynamic stable matter CeO2 and the least thermodynamic stable inclusion is CeS. And the thermodynamic stable sequence of the possible inclusions formed in liquid steel is CeO2 > Ce2O3 > Ce2O2S > Ce2S3 > Ce3S4 > CeS. Only when the amount of [O] is extremely low and the amount of [S] and [Ce] is relatively high, Ce2S3 has the possibility to form. With the amount of oxygen in molten iron increasing from 10 ppm to 200 ppm and the amount range of cerium increasing from 0.1% to 0.5%, Ce2O3 prefers to segregate in liquid phase all the time.By the addition of cerium in molten SS400 steel, when the temperature of molten iron reached 1873 K, at the same time that the Cerium addition in liquid iron is 70 ppm and the initial Oxygen and Sulphur are both 110 ppm, the formation of oxides containing Cerium would experience the transformation from CeHow to cite this article: Pan, F. et al. Thermodynamic Calculation among Cerium, Oxygen, and Sulfur in Liquid Iron. Sci. Rep.6, 35843; doi: 10.1038/srep35843 (2016).