Grey hematite photoanodes decrease the onset potential in photoelectrochemical water oxidation  

灰色赤铁矿光阳极降低光电化学水氧化起始电位

作　　者：Peng-Fei Liu Chongwu Wang Yun Wang Yuhang Li Bo Zhang Li-Rong Zheng Zheng Jiang Huijun Zhao Hua-Gui Yang 刘鹏飞;王重午;王云;李宇航;张波;郑黎荣;姜政;赵惠军;杨化桂(Key Laboratory for Ultrafine Materials of Ministry of Education,Shanghai Engineering Research Center of Hierarchical Nanomaterials,School of Materials Science and Engineering,East China University of Science and Technology,Shanghai 200237,China;Centre for Clean Environment and Energy,Griffith University,Gold Coast Campus,QLD 4222,Australia;State Key Laboratory of Molecular Engineering of Polymers,Department of Macromolecular Science and Laboratory of Advanced Materials,Fudan University,Shanghai 200438,China;Beijing Synchrotron Radiation Facility,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;Shanghai Synchrotron Radiation Facility,Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201204,China)

机构地区：[1]Key Laboratory for Ultrafine Materials of Ministry of Education,Shanghai Engineering Research Center of Hierarchical Nanomaterials,School of Materials Science and Engineering,East China University of Science and Technology,Shanghai 200237,China [2]Centre for Clean Environment and Energy,Griffith University,Gold Coast Campus,QLD 4222,Australia [3]State Key Laboratory of Molecular Engineering of Polymers,Department of Macromolecular Science and Laboratory of Advanced Materials,Fudan University,Shanghai 200438,China [4]Beijing Synchrotron Radiation Facility,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China [5]Shanghai Synchrotron Radiation Facility,Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201204,China

出　　处：《Science Bulletin》2021年第10期1013-1021,M0004,共10页科学通报（英文版）

基　　金：financially supported by the National Natural Science Funds for Distinguished Young Scholars (51725201);the International (Regional) Cooperation and Exchange Projects of the National Natural Science Foundation of China (51920105003);the Innovation Program of Shanghai Municipal Education Commission (E00014);the National Natural Science Foundation of China (51902105);the Shanghai Engineering Research Center of Hierarchical Nanomaterials (18DZ2252400);the Shanghai Sailing Program (19YF1411600)

摘　　要：Photoelectrochemical(PEC)water splitting for solar energy conversion into chemical fuels has attracted intense research attention.The semiconductor hematite(α-Fe_(2)O_(3)),with its earth abundance,chemical stability,and efficient light harvesting,stands out as a promising photoanode material.Unfortunately,its electron affinity is too deep for overall water splitting,requiring additional bias.Interface engineering has been used to reduce the onset potential of hematite photoelectrode.Here we focus instead on energy band engineering hematite by shrinking the crystal lattice,and the water-splitting onset potential can be decreased from 1.14 to 0.61 V vs.the reversible hydrogen electrode.It is the lowest record reported for a pristine hematite photoanode without surface modification.X-ray absorption spectroscopy and magnetic properties suggest the redistribution of 3d electrons in the as-synthesized grey hematite electrode.Density function theory studies herein show that the smaller-lattice-constant hematite benefits from raised energy bands,which accounts for the reduced onset potential.赤铁矿(α-Fe_(2)O_(3))是一种带隙小、稳定、廉价的光阳极材料,在光电化学分解水制氢领域有重要应用.然而较高的光电流起始电位制约了其光化学能转换效率的进一步提升.传统降低α-Fe_(2)O_(3)水氧化起始电位的策略包括纳米结构构建、体相异质原子掺杂及表界面调控等.本工作基于自主搭建的化学气相沉积装置,通过高温合成并骤冷压缩体相晶格的策略成功制备出灰色α-Fe_(2)O_(3)光阳极,进而调控了Fe3+的3d轨道电子排布,实验及理论数据证明3d轨道电子结构与能级位置的构效关系,而具有低自旋结构的α-Fe_(2)O_(3)有利于降低光电化学水氧化起始电位.灰色α-Fe_(2)O_(3)的光电流起始电位为0.61 V,是目前报道过未经表面修饰赤铁矿基光阳极的最优数值.该工作为高效光电极设计提供了新的研究思路,有利于推进光电化学分解水制氢工业化进程.

关 键 词：HEMATITE Photoelectrochemical water oxidation Onset potential Spin states Energy band 

分 类 号：TQ116.2[化学工程—无机化工] TQ138.11