Fe_2O_3半导体中光生电荷分离和传输研究进展

Progress in Photocarrier Separation and Transport on F_2O_3Semiconductors

利用自然界丰富的太阳能光电催化分解水制氢是解决能源问题的理想方法之一,也是光催化领域最具挑战性的课题之一。Fe2O3半导体由于其禁带宽度窄,具有优异的可见光吸收性能,而且对环境友好、来源丰富、价格低廉,有望成为未来光催化领域的重要材料。但Fe2O3半导体中光生电子-空穴的复合速率很快,导致其光化学能转化效率很低。综述了近年Fe2O3半导体中光生电荷分离和传输的研究进展,从杂原子掺杂、半导体复合、Fe2O3半导体微观形貌控制3个方面分析了影响Fe2O3半导体光催化剂光电转化效率的因素,提出有效抑制光生电子-空穴的复合是提高Fe2O3半导体光电催化分解水活性的关键。论述了Fe2O3半导体光催化剂的构成原理、设计思想、目前效果以及存在问题,展望了Fe2O3半导体光催化剂研究的发展趋势。

There is an increasing interest in the use of solar energy to drive the photolysis of water into molecular hydrogen by inorganic nanoparticles and photoelectrodes, which is the most ideal process to solve the energy crisis. However this reaction remains one of the biggest challenges in the photocatalysis field. Fe2O3 is one of the most promising materials for its application in energy and environmental fields due to its narrow band gap to absorb a large part of visible spectrum in sunlight as well as the abundant resource, the low price and environment friendliness. However, until now the reported solar-to-chemical energy conversion efficiencies of Fe2O3 are too low because of its ultrafast e/h recombination rate, which restrict the development of Fe203 photocatalysts. The recent progress in photocarrier separation and transport on Fe2O3 nano-semiconductors is reviewed in this paper. The influencing factors on the incident photo-to-current efficiency of Fe2O3 photocatalysts are discussed, including the heteroatom doping, the Fe2O3 sensitized by other semiconductors with different energy levels to form heterojunction, as well as the Fe2O3 with different nanostructures and nanosizes. The separation and the transport of the photo-generated electron hole pair play a pivotal role in the photoelectrocatalysis hydrogen production from water splitting on Fe2O3 semiconductors. A longer life of the photocarrier means a higher photocatalytic performance of Fe2O3. Finally, the principle, the design idea, the effects and the shortcomings of Fe2O3 are discussed, and the development direction of the Fe2O3 photocatalysts in the future is also addressed.