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

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 · O 2 − is the dominant reactive specie. • Ag/AgBr-I/S composite based on I/S were synthesized by deposition-precipitation method. • Ag/AgBr can improve the light absorption ability and photocatalytic property. • The photodegradation to Methyl orange of 25%-Ag/AgBr-I/S can reach 90% after 20 min. • The 25%-Ag/AgBr-I/S has good photocatalytic activity and chemical stability. [ABSTRACT FROM AUTHOR]