Photodeposition of gold nanoparticles on ZnS nanobelts for enhanced dye decomposition

Abstract

Gold nanoparticles have been produced on the surfaces of ZnS nanobelts via direct reduction during a photodeposition process. Because the gold nanoparticles have been fabricated in the absence of any reducing agents or surfactants, charge-separating junctions between gold and ZnS have been effectively produced. As the wt% of surface-decorating gold nanoparticles increases, the photoexcited charges of ZnS nanobelts can be separated efficiently. This has been demonstrated by monitoring photoluminescence spectra and kinetics. The long-lived excited charges promote the generation of reactive radical species, increasing the photocatalytic degradation of 4-nitrophenol. Compared with commercial ZnS, the optimized photocatalyst of Au-ZnS nanobelts exhibits 5.2 times higher photocatalytic activity. Overall, via a simple and facile photodeposition process, charge separating junctions between gold and ZnS have been formed effectively to increase the photocatalytic efficiency of ZnS greatly, suggesting that the photodeposition of gold is an effective method to enhnace photocatalytic dye deomposition activity.