Efficient utilization of photogenerated electrons and holes for photocatalytic redox reactions using visible light-driven Au/ZnIn2S4 hybrid

In this study, a new photocatalytic reaction system for simultaneous selective oxidation of aromatic alcohols to corresponding aldehydes and reduction of protons to H-2 has been developed. The results reveal that compared with pure ZnIn2S4, the ZnIn2S4 photocatalysts modified with noble metal gold (Au/ZnIn2S4) significantly promote the photocatalytic performance. Among them, the 0.5% Au/ZnIn2S4 nanosheets shows the highest photocatalytic activity for selective oxidation of benzyl alcohol to benzaldehyde and hydrogen production, and the yields of 112 and benzaldehyde are 326.68 and 352.04 mu mol under visible light irradiation for 4 h, respectively. Those are about 4.4 and 3.6 times higher than those of pure ZnIn2S4 sample (74.0 mu mol H-2 and 98.04 mu mol benzaldehyde), respectively. The utilization ratio of photogenerated electrons to holes can achieve 92.8%. Additionally, the control experiments demonstrate that the photogenerated electrons and holes play significant roles during the reaction process. It is hoped that the current work can offer an avenue to utilize the photogenerated carriers more efficiently and to develop other photocatalytic reaction systems, such as nitrogen fixation and reduction of carbon dioxide.