Synthesis and visible-light-induced sacrificial photocatalytic water oxidation of quinary oxynitride BaNb_(0.5)Ta_(0.5)O_2N crystals

Quinary oxynitride BaNb_0.5Ta_0.5O_2N crystals were fabricated through the partial nitridation and acidifica- tion of the KCI flux grown Ba_5Nb_2Ta_2O_15 crystals. The parameters of both the solute concentrations and cooling rates are optimized for the KCI flux growth of the larger Ba_5Nb_2Ta_2O_15 crystals with clearer crystal habits. Here, the optimal Ba_5Nb_2Ta_2O_15 crystals mainly have a hexagonal plate-like shape. After the par- tial nitridation and acidification, the porous BaNb_0.5Ta_0.5O_2N crystals maintained the crystal shape of the oxide precursor and had a single-crystalline nature. For the BasNb2Ta2015 crystals, the wavelength of the absorption edge was about 707 nm. Especially, the CoOx-Ioaded BaNb_0.5Ta_0.5O_2N photocatalyst demon- strated the comparatively high amount of O_2 gas （150.7 μmol） during the 5 h visible-light-induced sacri- ficial water oxidation half-reaction, which might be achieved due to the high crystallinity and visible-light absorotion property.

New mass loss kinetic model for thermal decomposition of biomass

Based on non-isothermal experimental results for eight Chinese biomass species, a new kinetic model, named as the 損seudo bi-component separate-stage model (PBSM)? is developed in this note to describe the mass loss behavior of biomass thermal decomposition. This model gains an advantage over the commonly used 損seudo single-component overall model (PSOM)?and 損seudo multi-component overall model (PMOM)? By means of integral analysis it is indicated that the new model is suitable to describe the mass loss kinetics of wood and leaf samples under relatively low heating rates (e.g. 10℃/min, used in this work).

Regression model for stabilization energies associated with anion ordering in perovskite-type oxynitrides

Certain perovskite-type oxynitrides have bandgaps suitable for renewable hydrogen production via photocatalytic and photoelectrochemical water splitting under visible light.Understanding the ordering of oxide and nitride anions in these materials is important because this ordering affects their semiconductor properties.However, the numerous possible orderings complicate systematic analyses based on density functional theory(DFT) calculations using defined elemental arrangements.This work shows that anion ordering in large-scale supercells within perovskite-type oxynitrides can be rapidly predicted based on machine learning, using BaNbO2N(capable of oxidizing water under irradiation up to 740 nm) as an example.Machine learning allows the calculation of the total energy of BaNbO2N directly from randomly selected initial atomic placements without costly structural optimization, thus reducing the computational cost by more than 99.99%.Combined with the Metropolis Monte Carlo method, machine learning permits exploration of the stable anion orderings of large supercells without costly DFT calculations.This work therefore demonstrates a means of predicting the properties of functional materials having complex compositions based on the most realistic elemental arrangements in conjunction with reasonable computational loads.

Metal selenides for photocatalytic Z-scheme pure water splitting mediated by reduced graphene oxide

Exploration of novel narrow bandgap semiconductors for overall water splitting is vital for the realization of practical solar H2 production. In the work, solid solutions of zinc selenide and copper gallium selenide with absorption edge wavelengths ranging from 480 to 730 nm were developed. Using these metal selenides as H2-evolving photocatalysts, CoOx/BiVO4 as the O2-evolving photocatalyst, and reduced graphene oxide as the electron mediator, all-solid-state Z-scheme overall pure water splitting systems were constructed. The rate of photocatalytic H2 evolution from aqueous solutions containing Na2S and Na2SO3 as the electron donors was evaluated while employing these selenide photocatalysts at various Zn/(Zn+Cu) and Ga/Cu molar ratios. The data demonstrate that efficient Z-scheme overall water splitting was significantly correlated to the photoelectrochemical performance of the selenide photocatalysts acting as photocathodes, rather than the photocatalytic activities of these materials during the sacrificial H2 evolution.

Design and strategy for manufacturing kidney organoids

Despite a continuing increase in the number of patients suffering from chronic kidney disease,currently available treatments for these patients,such as dialysis and kidney transplantation,are imperfect.The kidney is also a critical target organ vulnerable to the toxicity of various new drugs,and the lack of a reliable in vitro culture model imposes a severe limitation on drug discovery.Although the development of induced pluripotent stem cells(iPSCs)revolutionized strategies in biomedical fields,the complexity of the kidney imposed additional challenge to the application of this technology in kidney regeneration.Nonetheless,the recent advancement in our understanding on the developmental origin of kidney progenitor cells and the mechanisms of their reciprocal induction and self-organization has boosted research in kidney regeneration.Research since then has demonstrated that kidney organoids derived from iPSCs can serve as a useful model for drug discovery and toxicity screening,as well as for disease modeling,especially in combination with gene editing techniques.Moreover,attempts at kidney organoid implantation in animals have suggested their potential as an alternative source of kidney transplantation.In this review,we summarize recent progress on the generation of kidney organoids,as well as the obstacles that remain.

一种新的生物质热分解失重动力学模型

基于对８种中国生物质材料非等温热分解的实验结果，建立了描述生物质热解失重过程的“双组分分阶段反应模型”，这种模型相对于通常使用的“单组分全局反应模型”和“多组分全局反应模型’来说具有相当大的优点．利用积分型方法进行动力学分析表明，“双组分分阶段一级反应模型”适用于描述空气气氛下升温速率较低（如１０℃／ｍｉｎ）时生物质材料的树干和树叶试样的热分解失重动力学．

Cyclohexane Dehydrogenation in Solar-Driven Hydrogen Permeation Membrane Reactor for Efficient Solar Energy Conversion and Storage

Cyclohexane dehydrogenation in the solar-driven membrane reactor is a promising method of directly producing pure hydrogen and benzene from cyclohexane and storing low-grade solar energy as high-grade chemical energy.In this paper,partial pressure of gases,conversion rate of cyclohexane,and energy efficiency of the reactor are analyzed based on numerical simulation.The process of cyclohexane dehydrogenation under four temperatures(200℃,250℃,300℃,and 350℃)and four permeate pressures(0.050 MPa,0.025 MPa,0.010 MPa,and 0.001 MPa)were studied.A complete conversion rate(99.9%)of cyclohexane was obtained as the reaction equilibrium shifts forward with hydrogen separation.The first-law thermodynamic efficiency,solar-to-fuel efficiency,and exergy efficiency could reach as high as 94.69%,46.93%and 93.08%,respectively.This study indicates that it is feasible to combine solar energy supply technology with cyclohexane dehydrogenation reaction integrated with membrane reactor.

Square-Scheme Electrochemistry in Battery Electrodes

CONSPECTUS:Sustainable development cannot be achieved without substantial technological advancements.For instance,flexible electricity management requires smart power sourcing with advanced energy storage/conversion technologies.Remedies for abrupt power spikes/drops observed in renewable energy sources such as solar and wind require rapid load-leveling using high-power energy storage systems when they are integrated into a microgrid.Electrochemical energy storage devices efficiently convert electrical and chemical energy,which can potentially function as distributed power sources.Among these,lithium-ion batteries are a present de facto standard with their relatively high energy density and energy efficiencies that are based on topochemical intercalation chemistry,whereby guest lithium ions are(de)intercalated reversibly with simultaneous redox reactions and minimal structural changes.However,their energy density,power density,life-cycle cost,calendar life,and safety remain unsatisfactory for widespread use.When the storage capacity is maximized,as a result of which a labile deep charge/discharge state is generated,to develop batteries with high energy density,subsequent irreversible phase transformations or chemical reactions occur in many cases.The combination of the reversible electrode reactions and the subsequent irreversible phase transformations sometimes causes a charge/discharge curve characterized by a large voltage hysteresis with 100%Coulombic efficiency.Because a large voltage hysteresis significantly degrades the energy efficiency,unveiling the reaction mechanism is of primary importance in mitigating energy loss.