Adjusting inter-semiconductor barrier height via crystal plane engineering: Crystalline face exposed single crystal cadmium sulfide augmentative S-scheme heterojunctions for efficiently photocatalytic hydrogen production

Abstract

The design of crystalline face engineered photocatalysts can modulate the catalytic activity at the microscopic scale. The exposure ratio of (100), (002) and (101) crystal planes of CdS with visible light activity was adjusted by crystal plane engineering. Density functional theory (DFT) calculations and experiments show that the fully exposed (002) surface CdS-L (Leaf-like CdS) has excellent hydrogen evolution activity. The use of the interface heterojunction strategy can greatly mobilize the electron flow between CdS-L and CoS2 S-scheme heterojunction compound semiconductors by changing the potential barrier difference. The CoS2/CdS-L composite photocatalyst exhibits amazing hydrogen evolution activity under 5 W white light irradiation, and the hydrogen production rate can reach 19.22 mmol·g−1·h−1. The results of in situ radiation XPS tests and comparative experiments show that the catalysts with more exposed crystal planes on the basis of constructing S-scheme heterojunctions can provide more active sites and have stronger reactivity. The use of crystal facet engineering effect and interfacial heterojunction strategy lays the foundation for the structural design and large-scale application of highly active visible light catalysts.