Ho Wingkei, Yu Jimmy C, Lin Jun, Yu Jiaguo, Li Puishan
Department of Chemistry, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
Langmuir. 2004 Jul 6;20(14):5865-9.
A new approach has been developed for the fabrication of visible light photocatalysts. Nanoclusters of MoS2 and WS2 are coupled to TiO2 by an in situ photoreduction deposition method taking advantage of the reducing power of the photogenerated electrons from TiO2 particles. The photocatalytic degradation of methylene blue and 4-chlorophenol in aqueous suspension has been employed to evaluate the visible light photocatalytic activity of the powders. The blue shift in the absorption onset confirms the size quantization of MS2 nanoclusters, which act as effective and stable sensitizers, making it possible to utilize visible light in photocatalysis. Quantum size effects alter the energy levels of the conduction and valence band edges in the coupled semiconductor systems, which favors the interparticle electron transfer. In addition, the coupled systems are believed to act in a cooperative manner by increasing the degree of charge carrier separation, which effectively reduces recombination.
一种用于制备可见光光催化剂的新方法已经被开发出来。利用TiO2颗粒光生电子的还原能力，通过原位光还原沉积法将MoS2和WS2纳米团簇与TiO2耦合。采用水悬浮液中亚甲基蓝和4-氯苯酚的光催化降解来评估粉末的可见光光催化活性。吸收起始点的蓝移证实了MS2纳米团簇的尺寸量子化，其作为有效且稳定的敏化剂，使得在光催化中利用可见光成为可能。量子尺寸效应改变了耦合半导体系统中导带和价带边缘的能级，这有利于粒子间的电子转移。此外，据信耦合系统通过增加电荷载流子的分离程度以协同方式起作用，从而有效地减少复合。
