铋系半导体光催化剂的光催化性能调控

Control of Photocatalytic Property of Bismuth-Based Semiconductor Photocatalysts

铋系光催化剂具有良好的光催化性能,由于其Bi6s和O2p的轨道杂化,提高了价带的位置,从而减小了禁带宽度,使得铋系光催化剂在可见光范围内具有明显的吸收,已成为近年来光催化领域研究的热点。铋系光催化剂在可见光区的光催化活性虽然比传统的TiO2有明显的提高,但其量子效率不高,光生电子-空穴容易结合,对可见光的吸收有限等问题,使其离实际应用仍存在较大的距离。因此,必须采取合适的措施来提高铋系催化剂的光生载流子速率,抑制光生电子-空穴复合,增强对可见光的吸收。本文主要综述了近年来在铋系半导体光催化剂光催化性能调控方面的最新研究进展,重点就铋系半导体光催化剂的形貌控制、特殊晶面暴露、贵金属沉积、离子掺杂、非金属掺杂、半导体复合等方面进行分析和总结,并对铋系半导体光催化剂的发展方向进行展望。

Bismuth-based semiconductor, with superior photocatalytic activity and especially with good absorbance in visible light,have become the research hotspot in photocatalytic field recently. The valence band of bismuth-based semiconductor photocatalyst consist of Bi6s and O2p orbitals and the levels are more negative than that consisting of only O2p,w hich results in the decrease in the band gap. The visible-light-induced photocatalytic activity of bismuth-based semiconductor photocatalysts is higher than that of traditional TiO 2. How ever,the low quantum efficiency,the easy recombination of electrons and holes,and the low visible light absorption making the bismuth-based semiconductor photocatalysts far aw ay from practical use. Therefore,w e must take some measures to improve the efficiency of photocatalytic carriers,suppress the combination of photo electrons and holes,and increase the visible light absorption. This article review s the recent development of methods for improving the photoactivity of bismuth-based semiconductor photocatalysts, mainly including morphology control,special crystal face exposing,noble metal deposition,metal ion doping,nonmetal doping,semiconductor combination and so on. The relationship betw een these methods and photocatalytic activity is analyzed,and it may be useful for designing highly efficient bismuth-based semiconductor photocatalysts. Besides,the main problems of the bismuth-based semiconductor photocatalysts are discussed,and the direction of development of the bismuth-based semiconductor photocatalysts is pointed out.