α-Fe_2O_3光电催化分解水研究进展

α-Fe_2O_3 Photoelectrocatalytic Water Decomposition

利用光电催化技术分解水制氢来获得清洁能源,有助于缓解当前化石能源日益萎缩及二氧化碳排放污染环境带来的压力。α-Fe_2O_3具有带隙合适、化学稳定性好、资源丰富以及经济可行性好等特点,使其在光电极材料研究中一直备受青睐。但是,由于氧化铁材料导电性差,光生电子和空穴复合率高等原因,限制了该材料在光电催化技术中的发展应用。从光阳极材料分解水制氢的原理出发,综述了近年来通过形貌控制如制备多层薄膜、纳米管(核壳结构的纳米棒)及纳米网等,引入Sn、Si、Ti、Mn、Al、Zn等元素以及部分元素的共掺杂,引入氧空位及与IrO_2、Co-Pi、Al_2O_3、石墨烯等其他材料的复合等几种途径,促进光生载流子的迁移效率,减少载流子的复合机率,进一步提高光电流密度并降低起动电压,以达到改善α-Fe_2O_3性能的研究工作。

Decomposing water using solar energy based on photo-electrochemical process has raised wide concern as a possible means of obtaining clean and renewable hydrogen fuel. It helps relieving stress from fossil energy decrease and anthropogenic CO2 emissions to the environment. Recently, α-Fe2O3 has become a focus of photoelectrodes study due to its appropriate band gap, excellent chemical stability, abundant resource and economic feasibility. However, its poor electrical conductivity and high recombination rate of photo-generated electron/hole have restricted its development and application in photo-electrochemical water decomposition. Methods of improving performance of α-Fe2O3 photoelectrodes were summarized, including strategies of adjusting growth direction and morphology（such as multilayer films, nanotube（core-shell nanorods） and nanonet）, doping with Sn, Si, Ti, Mn, Al and Zn elements, inducing oxygen vacancies and compositing with IrO2, Co-Pi, Al2O3, graphene, etc. The methods could promote transfer of photo-generated carriers, reduce probability of carrier recombination, further improve reaction photocurrent density and decrease the initiative voltage, so as to improve study of improving α-Fe2O3 performance.