Construction of NiCo<sub>2</sub>S<sub>4</sub>/ZnCdS Schottky Junction with Unidirectional Interfacial Electron Transfer for Boosting Photocatalytic Hydrogen Production
Ya-Nan Qiao, Yan Zhang, Jun Yuan, Huimin Xue, Bin Jia
Abstract
The efficient separation of photogenerated electron–hole pairs is a critical challenge that hampers the performance of photocatalytic systems. In this work, a NiCo 2 S 4 /ZnCdS (NiCo 2 S 4 /ZCS) Schottky junction was constructed by a simple physical mixing method. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results proved that NiCo 2 S 4 is an amorphous material, and density functional theory (DFT) calculations confirmed the metallic nature of NiCo 2 S 4 . The light absorption capacity of the NiCo 2 S 4 /ZCS heterojunction is significantly enhanced with the NiCo 2 S 4 loading. The formation of Schottky junctions between NiCo 2 S 4 and ZnCdS results in photogenerated electron transfer and spatial separation and prevents the recombination of charge carriers. Therefore, the optimized 20% NiCo 2 S 4 /ZCS exhibits a remarkable photocatalytic hydrogen evolution (PHE) activity of 25 mmol g –1 h –1, which is 4.79 and 150.6 times higher than that of ZnCdS alone and NiCo 2 S 4 . This work provides a successful strategy for preparing a ZnCdS-based Schottky junction to promote PHE activity.