Surface modification of ZnIn2S4 layers to realize energy-transfer-mediated photocatalysis

Surface modification strategy of non-conductive PVP chains coating on ZnIn2S4 nanosheets can inhibit electron transfer and facilitate energy transfer process, where the enhanced long-lived states will boost O-1(2) generation and benefit the photocatalytic sulphoxidation of sulphides. Photocatalytic selective aerobic oxidation reactions are crucial in designing advanced organic intermediates, but suffer from low conversion efficiency. Hence, activating O-2 to create suitable reactive oxygen species, such as singlet oxygen (O-1(2)), can significantly increase the yield of desired products. Herein, using ZnIn2S4 nanosheets as a model system, we build a surface-modified theoretical structure, where a surface-covered non-conductive macromolecular chain, polyvinyl pyrrolidone (PVP), is bound to ZnIn2S4 and influences the O-2 adsorption process. PVP on the surface significantly changes the electronic structure and suppresses electron conduction of ZnIn2S4 nanosheets. Therefore, abundantly photogenerated and long-lived species transfer their energy to physically absorbed O-2 to efficiently generate O-1(2), which can oxidize sulphides into their corresponding sulphoxides. For sulphoxidation of different sulphides, surface modification brings a 3-9-fold increase in conversion efficiency and high selectivities >= 98%. This study provides a feasible way of boosting O-1(2)-generation-related photocatalytic reactions.

Automated summary

The surface modification strategy using non-conductive PVP chains on ZnIn2S4 nanosheets inhibits electron transfer and facilitates energy transfer, leading to enhanced O-1(2) generation and improved photocatalytic sulphoxidation of sulphides.