Synthesis and photocatalytic mechanism of visible-light-driven Ag/AgBr/(I/S) composites for organic dyes degradation

Abstract

Series of visible light responsive Ag/AgBr/(I/S) composites based on I/S were synthesized by deposition-precipitation method. Methyl orange (MO) and other organic dyes were used to evaluate the photoactivity of Ag/AgBr/(I/S) composites. The results showed that Ag/AgBr/(I/S) composites display a good photocatalytic activity for organic dyes degradation. As the content of Ag/AgBr was 25 wt%, Ag/AgBr/(I/S) composites exhibited the best the photocatalytic activity for organic dyes. The degradation rate of Rhodamine B (RhB) and MO were 90% and 92% after 20 min. Furthermore, cycling experiments revealed that the 25%Ag/AgBr/(I/S) composites had long-term recycling stability. The photocatalytic mechanism of Ag/AgBr/(I/S) composites to MO degradation was studied by free radical trapping experiments and electron paramagnetic resonance (EPR) test, which indicating that photogenerated ·O2− is the dominant reactive specie.