Preparation of Highly Active Catalyst CoS₂/CdS and Its Mechanism of Photocatalytic H₂ Evolution

Abstract

Photocatalytic water-splitting has great promise as a viable approach for H2 production. Herein, CoS2/CdS catalysts with exceptional catalytic performance were synthesized by a solvothermal method. The formed CdS phase junction and the successful loading of CoS2 were verified by XRD and HRTEM characterization techniques. The experiments demonstrated that the composite photocatalysts have high photocatalytic activity and stability. The highest H2 evolution rate of CoS2/CdS is 16.4 times and 2.1 times that of CdS and Pt/CdS, respectively. To elucidate the enhanced H2 evolution mechanism, the work function, optical properties, and carrier separation and migration of CoS2/CdS were investigated by DFT calculations, photoelectrochemical measurement, and Mott–Schottky experiments. It is revealed that the excellent H2 evolution behavior of CoS2/CdS catalysts results from CdS phase junction promoting the photogenerated carrier separation, and the metallic CoS2 that widens the optical absorption range and enhances the separation and transport of photogenerated carriers. In addition, it offers ample active sites for proton reduction.