In-situ anion exchange preparation of Ag2S/Ag2CrO4 core–shell heterojunction with enhanced visible-light photocatalytic activity

Abstract

Photocatalytic technology is one of the most promising technologies for wastewater treatment. In this paper, Ag₂S/Ag₂CrO₄ core–shell heterojunction were prepared using in-situ anion exchange method. The structure, morphology, and optical properties of the prepared samples were characterized by XRD, SEM, TEM, XPS, and DRS technologies. The photo-degradation results verified that the 2 %-Ag₂S/Ag₂CrO₄ heterojunction exhibited excellent photocatalytic activity for degradation of organic dyes and antibiotics under visible light irradiation. The removal efficiency for RhB was 95 % in 15 min, which was obviously superior to that of pure Ag₂CrO₄ (∼73 %) and Ag₂S (∼7%) photocatalysts. The enhanced photocatalytic performance of the Ag₂S/Ag₂CrO₄ was mainly attributed to the Z-scheme core–shell heterojunction structure of the photocatalyst that facilitated excellent charge carriers separation and migration. Meanwhile, the results of trapping experiments for active species demonstrated that both the holes (h⁺) and superoxide radical (O₂⁻) played an important role for degradation of organic pollutants.