光电化学反应的催化

本文主要按照催化剂与半导体电极二者之间所形成的结的性质, 分析了催化剂对电极表面上进行的光电化学反应可能具有的效应。分析结果表明, 催化光电化学反应(光生少数载流子的反应)的前提是催化剂微粒与“半导体/溶液”界面之间有足够强的相互作用, 因而在光照下催化剂粒子中电子系统的费米能级能达到或趋近光生少数载流子的准费米能级。文中并采用带环的可换旋转园盘电极研究了Au、Ir等金属微粒对在n-TiO_2单晶电极上进行的Ce~(3+)—→Ce~(4+)等光电化学反应的催化机理, 证实了上述分析结果。

THE CATALYSIS OF PHOTOELECTROCHEMICAL REACTIONS

The possible effect of catalyst on the kinetics of photoelectroehemieal (PEC) reactions taking place at the surface of semiconductor (SC) electrodes was analysed mainly by considering the nature of junction between SC and catalyst particles. Result of analysis showed that in many cases catalyst could only eatalyse dark reactions. Prerequisite for catalysis of PEC reactions would be sufficiently strong interaction of catalyst particles with the SC/solution junction("liquid junction"), so that the Fermi level of electron system within catalyst particles could approach the quasi-Fermi level of photo-generated minority carriers. Experimental results of investigation of the effects of deposited Au, Ir, Pd and Pt on the kinetics of Ce~(3+)→Ce~(4+) and other reactions taking place on monocrystalline n-TiO2 electrode strongly supported such a model. Technique of RRDE with inter-changeable SC disks was empolyed in investigating catalysis of PEC reactions.