Performance of Ag/BiOBr/GO composite photocatalyst for visible-light-driven dye pollutants degradation

Abstract

Based on BiOBr, an Ag/BiOBr/GO composite catalyst was constructed by doping the noble-metal Ag and the non-metal GO. A Xenon lamp was used to simulate a source of visible light, and Rhodamine B was used as target pollutant. The catalytic activity of the novel catalyst was investigated via degradation experiment. The catalysts were characterized and analyzed by XRD, SEM, TEM, XPS, FT-IR, UV vis-DRS, and EIS. Compared with BiOBr, Ag/BiOBr, and GO/BiOBr, the prepared Ag/BiOBr/GO catalyst (doped with 2.0 wt.% GO and 1.5 wt.% Ag) exhibited the highest photocatalytic activity, with a RhB degradation rate of up to 98% within 120 min. Adding the metal Ag and GO significantly improved the photocatalytic activity of the BiOBr catalyst. This is a result of the Schottky barrier, surface plasmon resonance, and good electrical conductivity of the metal Ag as well as the large specific surface area and excellent electron transport efficiency of the non-metal GO. Their combination promoted the transfer and separation of photo-generated carriers of catalyst, and effectively limited the recombination rate of the photogenerated electron–hole. In a subsequent repeatability experiment, the catalysts still showed good photocatalytic activity and stability after five times of reuse, indicating that the composite catalyst has good stability and reusability value. Keywords: BiOBr, Ag, GO, Photocatalyst, Water treatment