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Heterostructured MOFs photocatalysts for water splitting to produce hydrogen

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Journal of Energy Chemistry 2021年第7期30卷 508-522页

作者： Yu Xiao Xiangyang Guo Nengcong Yang fuxiang zhang State Key Laboratory of Catalysis iChEMDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian National Laboratory for Clean EnergyDalian 116023LiaoningChina Department of Inorganic Chemistry and Physical Chemistry College of PharmacyHarbin Medical UniversityHarbin 150081HeilongjiangChina

Metal-organic frameworks(MOFs) with high designability and structure diversity have been widely developed as promising photocatalytic materials,but most of them suffer from poor charge transportation and separation *** address it,the construction of MOFs-based heterostructures has been thus highly *** this minireview,we will first introduce the basic principles of photocata lytic water splitting and heterostructure systems,and then discuss state-of-the-art MOFs-based heterostructures for photocata lytic water splitting to produce ***,special attention will be paid to the key factors affecting the interfacial charge transfer of heterostructures,such as interface connection mode,morphology control,and ***,the challenges and prospects faced by the construction of high-efficiency MOFs-based heterostructure water slitting photocatalysts are proposed.

关键词： MOF Heterostructure Water splitting Photocatalytic hydrogen production

Visible Light-Responsive N-Doped TiO_(2) Photocatalysis:Synthesis,Characterizations,and Applications

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Transactions of Tianjin University 2022年第1期28卷 33-52页

作者： Shiwen Du Juhong Lian fuxiang zhang State Key Laboratory of Catalysis iChEMDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian National Laboratory for Clean EnergyDalian 116023China

Photocatalysis based on semiconductors has recently been receiving considerable research interest because of its extensive applications in environmental remediation and renewable energy *** semiconductor-based materials that are vital to solar energy utilization have been extensively investigated,among which titanium oxide(TiO_(2))has attracted considerable attention because of its exceptional physicochemical ***,the sluggish responsiveness to visible light in the solar spectrum and the inefficient separation of photoinduced electron-hole pairs hamper the practical application of TiO_(2) *** overcome the aforementioned serious drawbacks of TiO_(2),numerous strategies,such as doping with foreign atoms,particularly nitrogen(N),have been improved in the past few *** review aims to provide a comprehensive update and description of the recent developments of N-doped TiO_(2) materials for visible lightresponsive photocatalysis,such as(1)the preparation of N-doped/co-doped TiO_(2) photocatalysts and(2)mechanistic studies on the reasons for visible light ***,the most recent and significant advances in the field of solar energy applications of modified N-doped TiO_(2) are *** analysis indicated the critical need for further development of these types of materials for the solar-to-energy conversion,particularly for water splitting purposes.

关键词： N-doped TiO_(2) Visible light-responsive Photocatalysis Solar energy

Kinetics for hydrogen production by methanol steam reforming in fluidized bed reactor

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Science Bulletin 2016年第5期61卷 401-405页

作者： fuxiang zhang Yingshuang Shi Lijun Yang Xiaoze Du Key Laboratory of Condition Monitoring and Control for Power Plant Equipment (North China Electric Power University) Ministry of Education

Hydrogen is one of the best energy *** bed reactor provides a promising approach for hydrogen production. To describe the hydrogen generating rate with methanol steam reforming in fluidized bed reactor quantitatively, dual-rate kinetic models of the reactions with exponent form were developed, including that of steam reforming reaction(SR) and decomposition reaction(DE).The reaction rate per unit mass of catalyst was related to partial pressures of components. The exponentials in kinetic equations were obtained by linear least-squares method based on the experimental data. The variance homogeneity test(F test) shows that the dynamic models are feasible with high accuracy, which can be used to predict the generating rate of hydrogen under different reaction temperatures and feed flow rates in fluidized bed reactor. The SR and DE activation energy obtained indicates that ESR\ EDE, which can explain the previous observation that the CO_2 selectivity decreased with the temperature increase.

关键词： Kinetics model Methanol steam reforming Hydrogen production Fluidized bed reactor

Synthesis of perovskite BaTaO_(2)N with low defect by Zn doping for boosted photocatalytic water reduction

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Journal of Energy Chemistry 2021年第12期30卷 358-363,I0009页

作者： Yunfeng Bao Hai Zou Nengcong Yang Gao Li fuxiang zhang State Key Laboratory of Catalysis iChEMDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian National Laboratory for Clean EnergyDalian 116023LiaoningChina University of Chinese Academy of Sciences Beijing 100049China

Perovskite BaTaO_(2) N(BTON) is one of the most promising photocatalysts for solar water splitting due to its wide visible-light absorption and suitable conduction/valence bands,but it still confronts the challenge of high defect density causing decreased charge separation as well as photocatalytic *** this work,we develop a simple zinc doping strategy to greatly suppress its defect density and promote its water reduction *** is found that the defect formation on the nitrided Ba(Zn_(1/3-x)Ta_(2/3))O_(3-y)N_z(denoted as BZTON hereafter) will be greatly inhibited when the Zn-doped Ba(Zn_(1/3)Ta_(2/3))O_(3)(BZTO) oxide is used as the nitridation *** structural characterizations and discussion demonstrate that the effective inhibition of Ta^(5+)into Ta^(4+)defects in BZTON mainly results from the easy reduction of zinc ions into metal and further the evaporation of zinc metal under the thermal ammonia ***,this simply doping methodology can be easily extended into the synthesis of SrTaO_(2) N(STON) with extremely low defect density,demonstrating its *** from the successful control to the defect density,the as-obtained BZTON photocatalyst exhibits remarkably promoted charge separation as well as water reduction activity to produce hydrogen with respect to the pristine *** work may provide an alternative avenue to prepare oxynitride semiconductors with reduced defect density for promoted solar energy conversion.

关键词： Oxynitride Photocatalyst Water splitting Defect density Zinc doping

Species,engineering and characterizations of defects in TiO2-basedphotocatalyst

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Chinese Chemical Letters 2018年第5期29卷 671-680页

作者： Beibei Dong Taifeng Liu Can Li fuxiang zhang State Key Laboratory of Catalysis 2011-iChEM Dalian National Laboratory for Clean Energy Dalian Institute of Chemical Physics Dalian 116023 China University of Chinese Academy of Sciences Beijing 100049 China National & Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials Collaborative Innovation Center of Nano FunctionalMaterials and Applications of Henan Province Henan University Kaifeng 475004 China

Light absorption, charge separation and surface reaction are considered as the main processes ofphotocatalysis on one semiconductor, and all of them are demonstrated to be related to the defect statesof photocatalysts. This paper will choose Ti02 as model photocatalyst to introduce some basic conceptsand strategies related to defects and methods developed to characterize defects in the past ***, such strategies as hydrogenation and metal/nonmetal doping intoTi02 will be introduced toextend utilization of solar spectrum and/or to provide active sites. On the contrary, the unfavorable effectof defects such as acting as recombination centers of photogenerated carriers will also be *** typical methods to characterize the properties of defects are summarized, which contain electronparamagnetic resonance （EPR）, photoluminescence technique （PL）, positron annihilation spectroscopy（PAS）, and so on. We do hope that this review will make a revealing effect on understanding to thefunctions of defects as well as construction of efficient photocatalytic systems in the future.

关键词： Titanium dioxide Defect engineering Photocatalysis Water splitting Environmental purification

Model gradient: unified model and policy learning in model-based reinforcement learning

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Frontiers of Computer Science 2024年第4期18卷 117-128页

作者： Chengxing JIA fuxiang zhang Tian XU Jing-Cheng PANG Zongzhang zhang Yang YU National Key Laboratory for Novel Software Technology Nanjing UniversityNanjing 210023China Polixir Technologies Nanjing 210000China

Model-based reinforcement learning is a promising direction to improve the sample efficiency of reinforcement learning with learning a model of the *** model learning methods aim at fitting the transition data,and commonly employ a supervised learning approach to minimize the distance between the predicted state and the real *** supervised model learning methods,however,diverge from the ultimate goal of model learning,i.e.,optimizing the learned-in-the-model *** this work,we investigate how model learning and policy learning can share the same objective of maximizing the expected return in the real *** find model learning towards this objective can result in a target of enhancing the similarity between the gradient on generated data and the gradient on the real *** thus derive the gradient of the model from this target and propose the Model Gradient algorithm(MG)to integrate this novel model learning approach with policy-gradient-based policy *** conduct experiments on multiple locomotion control tasks and find that MG can not only achieve high sample efficiency but also lead to better convergence performance compared to traditional model-based reinforcement learning approaches.

关键词： reinforcement learning model-based reinforcement learning Markov decision process

Development of Sn^(2+)-based oxyfluoride photocatalyst with visible light response of ca.650 nm via strengthened hybridization of Sn 5s and O 2p orbitals

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Journal of Energy Chemistry 2021年第12期30卷 385-390,I0009页

作者： Yanpei Luo Xin Zhou jiangwei zhang Yu Qia Zheng Lia fuxiang zhang Can Li State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian National Laboratory for Clean EnergyThe Collaborative Innovation Center of Chemistry for Energy Materials(iChEM)Dalian 116023LiaoningChina University of Chinese Academy of Sciences Beijing 100049China College of Environment and Chemical Engineering Dalian UniversityDalian 116622LiaoningChina

The hybridization between the outmost s orbitals of metal(Bi^(3+),Sn^(2+),Pb^(2+),Ag^(+))and O 2 p orbitals has been widely employed to develop innovative semiconductors with upshift valence band as well as extended visible light response,but it is still challenging to obtain photocatalyst with absorption edge of above 550 *** we report a novel Sn^(2+)-based oxyfluoride Sn_(2)TiNbO_6 F(STNOF)photocatalyst with a pyrochlore structure to exhibit an extended absorption edge to 650 nm and dual functionalities of both water reduction and *** functional theory calculations suggest that the unprecedented broad-spectrum response of STNOF is mainly ascribed to the strengthened hybridization between O 2 p and Sn 5 s orbitals remarkably upshifting the valence band,which is caused by the distortion and compressive strain in the Sn06 F2 dodecahedron with second-order Jahn-Teller effect due to partial fluorine *** structural distortion and compressive strain are experimentally confirmed by the Fourier-transformed extended X-ray absorption fine *** probe tests of the photocatalytic functionalities,water reduction and oxidation half reactions were examined to see obvious H_(2)and O_(2)evolution under visible light *** work may provide an alternative strategy of developing extended visible light responsive semiconductors for promising solar energy conversion.

关键词： Photocatalyst Visible light Water splitting DFT Structural characterizations

One dimensional nickel phosphide polymorphic heterostructure as carbon-free functional support loading single-atom iridium for promoted electrocatalytic water oxidation

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Journal of Energy Chemistry 2023年第4期79卷 410-417页

作者： Rashid Mehmood Guifa Long Wenjun Fan Mingrun Li Lifang Liu fuxiang zhang StateKey Laboratory of Catalysis iChEMDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian National Laboratory for Clean EnergyDalian 116023LiaoningChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China GuangxiKey Laboratory of Chemistry and Engineering of Forest Products School of Chemistry and Chemical EngineeringGuangxi Minzu UniversityNanning 530008GuangxiChina

Although conducting materials such as carbon nanotube and carbon fiber paper(CFP)have been extensively employed as support of electrocatalytic active sites,most of them are of poor catalytic functionality by themselves and undesirable stability during strong acid/alkaline environments or oxidation *** we report a novel one-dimensional(1D)nickel phosphide polymorphic heterostructure(denoted as NPPH)to work as one effective carbon-free functional support for loading of single-atom Ir water oxidation ***,the NPPH composed of both Ni12P5and Ni2P phases is not only active for robust alkaline water oxidation but also is of good stability and hydrophilicity for favorable loading of single-atom dispersed *** NPPH supported single-atom Ir electrocatalyst(Ir/NPPH)is found to exhibit remarkably superior water oxidation activity with respect to the NPPH itself or CFP supported single-atom Ir catalyst(Ir/CFP),demonstrating the synergetic promotion effect between NPPH and single-atom Ir ***,the NPPH supported single-atom Ir catalyst can bear alkaline water oxidation for over 120 h at current density of 50 mA cm^(-2).The NPPH developed here is expected as functional support to composite with other water oxidation catalysts,as may be an alternative strategy of developing highly efficient carbon-free electrocatalysts.

关键词： Oxygen evolution reaction Single atom catalyst Nickel phosphide Heterostructure One-dimensional

Influence of Sulfation on the Catalytic Activity of Ni-ZrO_2 for NO Reduction with Propane in Excess Oxygen

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Journal of Natural Gas Chemistry 2005年第4期14卷 221-225页

作者： Shujuan zhang Landong Li fuxiang zhang Naijia Guan Institute of New Catalytic Materials Science College of Chemistry Nankai University Tianjin 300071 China

Selective catalytic reduction （SCR） of nitric oxide with propane in excess oxygen was investigated on Ni-ZrO2 （NZ） and sulfated Ni-ZrO2 （SNZ）, prepared by coprecipitation from a mixture of nickel nitrate-zirconium oxychloride followed by modifying with （NH4）2SO4. It was found that sulfated Ni-ZrO2 catalyst showed higher activity for the SCR of NO with propane than that of Ni-ZrO2. The structural and surface properties of catalysts were studied by XRD, BET, SEM and FT-IR of pyridine adsorption. The experimental results indicated that the modification of （NH4）2SO4 resulted in the generation of strong BrOnsted and Lewis acid sites and promoted the dispersion of the Ni species, which could lead to higher NO conversion and propane efficiency in NO reduction.

关键词： sulfation Ni-ZrO2 coprecipitation SCR NO propane .