Photocatalytic performance of Ag2S under irradiation with visible and near-infrared light and its mechanism of degradation

Abstract

Ag₂S has only rarely been investigated as a photocatalyst on its own, although it has been widely used as an important component of composite photocatalysts. We synthesized Ag₂S by a facile ion-exchange method at room temperature and used it directly as an effective photocatalyst. Our results confirmed the excellent performance of Ag₂S in completely photodegrading methyl orange within 30 min under irradiation with visible light and within 70 min under irradiation with near-infrared light. This good performance is ascribed to the narrow band gap (1.078 eV) of Ag₂S and the lower recombination efficiency of the photogenerated electron–hole pairs of Ag₂S in the photocatalytic process. The active species in the photo-oxidation process was identified as anioic ozone radicals. This simple preparation method and high photocatalytic performance increases the possible future applications of Ag₂S.