Rodlike AgI/Ag 2 Mo 2 O 7 Heterojunctions with Enhanced Visible-Light-Driven Photocatalytic Activity

Abstract

Novel AgI/Ag 2 Mo 2 O 7 heterojunctions were prepared by reacting Ag 2 Mo 2 O 7 microrods with an aqueous KI solution at room temperature. The composite materials, compared with neat AgI and Ag 2 Mo 2 O 7 , 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, Ag 2 Mo 2 O 7 , and AgI/Ag 2 Mo 2 O 7 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 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.