Ag/AgCl/Ag2MoO4 composites for visible-light-driven photocatalysis

Ag2MoO4 shows low photocatalytic activity under visible light. It would be interesting to develop Ag2MoO4-based composite/heterojunction photocatalysts working efficiently under visible light. Herein, novel Ag/AgCl/Ag2MoO4 composites were obtained via photoreduction of AgCl/Ag2MoO4 composites prepared by sequential precipitation. The composition, morphologies, and optical properties of the samples were studied via various characterization techniques. Photocatalytic degradation of rhodamine B (RhB), methylene blue (MB), methyl orange (MO), norfloxacin (NOF), and tetracycline hydrochloride (TC) solutions was conducted under visible-light irradiation. An optimal Ag/AgCl/Ag2MoO4 catalyst showed much higher photocatalytic activity than Ag2MoO4, and it also showed reasonably fine recyclability. Through radical-capturing experiments, photo-generated holes (h(+)) were determined to be the main active species whereas hydroxyl radicals ((OH)-O-center dot) were found to play a secondary role in photocatalysis. Possible photocatalytic mechanisms were proposed.