Construction of a Surface Hydroxyl Group on ZnIn<sub>2</sub>S<sub>4</sub> Promotes Photocatalytic CO<sub>2</sub> Reduction
Xiaoyu Liang, Yulei Ren, Zhiwei Chen, Xinxin Zhang, Yan Liang, Bo Jiang, Hua Xie, Min Ji, Min Wang, Xinkui Wang
Abstract
Photocatalysis holds significant promise for the reduction of CO 2 to valued chemicals under mild conditions. However, its potential is severely limited by weak CO 2 adsorption and slow proton-coupled electron transfer (PCET) rates. In this work, ZnIn 2 S 4 -based catalysts with varying hydroxyl contents were synthesized via the solvothermal method. The hydroxyl group, acting as a basic site, improves CO 2 adsorption and inhibits the hydrogen evolution reaction (HER). Additionally, the hydroxyl group serves as a proton acceptor, facilitating proton transfer; the internal electric field formed by the redistribution of hydroxyl-induced charges promotes the separation of photogenerated carriers, jointly accelerating the PCET process. The hydroxyl-rich ZnIn 2 S 4 catalyst exhibits superior CO 2 reduction performance, with a CO generation rate of 4.55 mmol g –1 h –1, 20 times that of ZnIn 2 S 4 with a lower hydroxyl content. Furthermore, the CO:H 2 ratio is increased by 18. This study highlights the critical roles of PCET and effective CO 2 adsorption in the CO 2 reduction reactions.