A low-temperature and one-step method for fabricating ZnIn2S4–GR nanocomposites with enhanced visible light photoactivity

Abstract

ZnIn₂S₄–graphene (GR) nanocomposites have been fabricated by a low-temperature and one-step wet chemistry process, during which the formation of ZnIn₂S₄ nanosheets, the reduction of graphene oxide (GO) and intimate interfacial contact between them were achieved simultaneously. The as-prepared ZnIn₂S₄–GR exhibited remarkably enhanced visible light photocatalytic performance toward selective reduction of nitroaromatics to amines in water compared to blank ZnIn₂S₄. Controlled experiments have been carried out and revealed that an inert atmosphere and the addition of a hole scavenger are two important conditions for photocatalytic selective reduction of nitroaromatics over ZnIn₂S₄–GR. In comparison with blank ZnIn₂S₄, the remarkably enhanced photocatalytic performance of ZnIn₂S₄–GR can be mainly attributed to the integrative effect of the unique physicochemical properties of GR and the intimate interfacial contact between ZnIn₂S₄ and GR. Specifically, the introduction of GR into the matrix of ZnIn₂S₄ can significantly influence the morphology and structure of the samples owing to the “structure-directing” role of GO, enhance the adsorptivity of the substrate, and effectively promote the separation and transfer of photogenerated charge carriers, thereby contributing to the photoactivity enhancement. It is hoped that the current work on the facile synthesis of ZnIn₂S₄–GR nanocomposites can broaden the applications of ZnIn₂S₄–GR and other GR-based nanocomposites as visible-light-driven photocatalysts toward selective organic transformations under mild conditions.