Enhanced visible light photocatalytic performance of CdS sensitized TiO2 nanorod arrays decorated with Au nanoparticles as electron sinks

Abstract

In this paper, we propose a nanostructure with Au nanoparticles (NPs), as electron sinks, located at the most outside layer of CdS sensitized TiO₂ nanorod arrays (TiO₂ NRAs/CdS/Au). By the introduction of Au NPs, TiO₂ NRAs/CdS/Au performs higher visible light photocatalytic capacity in the degradation of unsymmetrical dimethylhydrazine wastewater than TiO₂ NRAs/CdS. The optimal deposition time for Au NPs is 30 s. The visible light induced degradation ability of TiO₂ NRAs/CdS/Au (30 s) is 1.4 times that of TiO₂ NRAs/CdS. The cycling stability of TiO₂ NRAs/CdS is greatly enchanced after Au NPs decoration, which can maintain 95.86% after three cycles. Photoluminescence spectra and photoelectrochemical measurements were carried out to reveal the underlying mechanism for the improved visible light photocatalytic capacity of TiO₂ NRAs/CdS/Au. This work demonstrates a promising way for the rational design of metal-semiconductor photocatalysts used in decomposition reaction that can achieve high photocatalytic efficiency.