Ag2S quantum dots in situ coupled to hexagonal SnS2 with enhanced photocatalytic activity for MO and Cr(vi) removal

Abstract

A novel visible-light-driven Ag₂S/SnS₂ composite photocatalyst was successfully fabricated via a simple in situ hydrothermal-ion-exchange method. The materials were systematically characterized by various techniques. XRD, XPS, and TEM analysis demonstrated the successful formation of Ag₂S quantum dots on the surface of SnS₂ nanoplates. The Ag₂S/SnS₂ composite materials exhibited increased photocatalytic activity compared to pure SnS₂ for the removal of methyl orange (MO) and Cr(VI), and the 1% Ag₂S/SnS₂ composite material showed the best activity under visible light irradiation. Holes (h⁺) and superoxide radicals (˙O₂⁻) were the major active species during the photocatalytic process. The in situ formation of Ag₂S quantum dots provided an effective way to facilitate carrier transfer and separation, which is believed to be responsible for the enhanced photocatalytic performance.