Rodlike AgI/Ag2Mo2O7 Heterojunctions with Enhanced Visible-Light-Driven Photocatalytic Activity

Novel AgI/Ag2Mo2O7 heterojunctions were prepared by reacting Ag2Mo2O7 microrods with an aqueous KI solution at room temperature. The composite materials, compared with neat AgI and Ag2Mo2O7, showed much higher activities in the photocatalytic degradation of aqueous rhodamine B, methyl orange, tetracycline hydrochloride, and levofloxacin solutions under visible-light irradiation. The structures, morphologies, and other physicochemical properties of AgI, Ag2Mo2O7, and AgI/Ag2Mo2O7 composites were studied via various characterization techniques. The active species involved in the photocatalytic process were examined via radical-capturing experiments and electron spin resonance. Superoxide anion radicals (O-center dot(2)-) and photogenerated holes (h(+)) were found to be the main active species. Photocatalytic mechanisms were proposed and reasons for the enhanced photocatalytic activity were explained.