A comparative study on the photocatalytic activities of two visible-light plasmonic photocatalysts: AgCl-SmVO4 and AgI-SmVO4 composites

Two novel plasmonic photocatalysts, AgCl-SmVO4 and AgI-SmVO4 composites, were prepared in this study. The two photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and UV-vis diffuse reflectance spectroscopy. The results showed that the prepared samples have a similar phase composition. The two photocatalysts both consist of SmVO4, AgX (X= Cl, I), and Ag. However, their photocatalytic activities varied significantly. The photocatalytic testing result showed that the AgI-SmVO4 hybrid exhibited a photocatalytic activity approximately three times higher than that of AgCl-SmVO4 in the photodegradation of rhodamine B under visible-light illumination. In addition to the strong adsorption ability for dyes, the suitable band potential of AgI and SmVO4 was considered as another important reason for the higher photocatalytic activity of AgI-SmVO4. It was suggested that this excellent property would lead to a high separation efficiency of electron-hole pairs, improving the photocatalytic activity. This speculation was further verified by the photocurrent-time and active species trapping measurements. (C) 2013 Elsevier B.V. All rights reserved.