Fabricated rGO-modified Ag₂S nanoparticles/g-C₃N₄ nanosheets photocatalyst for enhancing photocatalytic activity

Photocatalytic technology provides a new strategy for the treatment of water pollution and energy crisis. Developing photocatalytic materials with high efficiency and stable visible light response has always been the direction of scientific researchers in the photocatalytic field. In this paper, we designed and prepared an efficient and stable rGO-modifited type-I Ag₂S/g-C₃N₄ heterojunction photocatalyst (rGO/Ag₂S/CN). The TEM (Transmission electron microscope) technology shows that the morphology of rGO/Ag₂S/CN is a sandwich-like structure. UV-Vis DRS (UV-visible diffuse-reflectance spectrum) shows that the loading of Ag₂S NPs and the modification of rGO effectively enhance the light response performance of nanocomposite materials in visible light. PL (Photoluminescence) and PEC (Photoelectrochemical) results prove that the photogenerated carriers transport and separation efficiency of rGO/Ag₂S/CN have been improved. The photodegradation of RhB and the photoreduction of CO₂ results confirmed that this ternary nanocomposite has great photocatalytic activity. The photodegradation efficiency of the RhB aqueous solution is about 98.5% after 30 min under the visible light irradiation. The photoreduction experiments showed that the yields of CO and CH₄ are 178.05 μmol/g and 121.11 μmol/g, respectively after 8 h under the UV light irradiation. The results of cyclic photocatalytic experiments and the XRD pattern after those processes further revealed that the modification of rGO not only enhanced the photocatalytic performance of the nanocomposite photocatalyst, but also effectively improved the stability of Ag₂S in the photocatalytic process. The possible photocatalytic reaction mechanisms were discussed in detail.