Cocatalyst modification and nanonization of Ag/AgCl photocatalyst with enhanced photocatalytic performance

Usually, cocatalyst modification and nanonization of photocatalytic materials have been demonstrated to be two kinds of effective strategies to improve the photocatalytic performance. For the well-known Ag/AgCl photocatalyst, it is difficult to obtain AgCl nanoparticles by a conventional precipitation reaction in aqueous solutions. It is highly required to develop a facile and effective strategy to simultaneously realize the cocatalyst modification and nanonization of Ag/AgCl photocatalysts. In this study, cocatalyst modification and nanonization of Ag/AgCl photocatalyst were simultaneously realized via a facile reduction-reoxidization route by using graphene oxide (GO) as the cocatalyst modifier. It was found that the chemical reduction of both Ag+ and GO by NaBH4 leaded to the formation of nanoscale Ag grafted on the reduced GO (rGO), whereas the following in situ reoxidization of metallic Ag in FeCl3 solution resulted in the final formation of well-dispersed Ag/AgCl nanoparticles on the rGO surface. Owing to a good encapsulation of Ag nanoparticles by rGO nanosheets, the resultant AgCl nanoparticles could be easily controlled to be 20-200 nm and were tightly grafted on the rGO cocatalyst surface. The photocatalytic experimental results indicated that all the Ag/AgCl-rGO (1-5 wt% rGO) nanocomposites exhibited a much higher photocatalytic decomposition of phenol than the Ag/AgCl under visible light irradiation, and the Ag/AgCl-rGO (3 wt% rGO) showed the highest performance. The enhanced photocatalytic activity of Ag/AgCl-rGO can be attributed to the cooperation effect of rGO nanosheet cocatalyst promoting the effective transfer of photogenerated electrons, and the nanonization of AgCl particles that provide more surface active sites for the decomposition of organic substances. This work may provide new insights into the fabrication of high-performance visible-light photocatalytic materials. (C) 2013 Elsevier B.V. All rights reserved.