Fabrication of Ag nanowires–CdS–Au photocatalyst and its excellent visible light photocatalytic activity: The role of synergetic electron transfer

Abstract

A novel Ag nanowires–CdS–Au (Ag NWs–CdS–Au) photocatalyst was synthesized by a two-step solvothermal method. As a metal core, thioglycolic acid (TGA) functionalized Ag NWs provided abundant active sites, facilitating the attachment of CdS; and the excessive S2− on the surface of CdS favored the loading of Au, leading to the well-developed combined interface of Ag NWs–CdS and CdS–Au. The combination and interaction between Ag NWs–CdS and CdS–Au was beneficial to the electron transfer in the photocatalysis. Multiple electron transfer processes happened in the Ag NWs–CdS–Au photocatalyst, enhancing charge carrier separation efficiency. Therefore, Ag NWs–CdS–Au possessed much higher photocatalytic degradation efficiency (89%) of MB than that of Ag NWs–CdS (45%) under visible light irradiation. Additionally, the Ag NWs–CdS–Au photocatalyst could absorb more visible light, favoring the generation of leuco-methylene blue (LMB) molecules, and further promoting the formation of ·OH. The finding provides a novel method to obtain bimetallic photocatalyst with separated bimetals to achieve high visible light photocatalytic activity and stability.