Construction of Zn0.5Cd0.5S nanosheets and the hybridization with onion-like carbon for enhanced photocatalytic hydrogen production

ZnCdS alloy is an attractive photocatalyst for hydrogen generation because of the tunable band gap and high photostability. However, the nanosheet construction and further hybridization with carbon materials still remain challenging. In this work, the synthesis of Zn0.5Cd0.5S hexagonal nanosheets and the hybridization with onion-like carbon (OLC) were studied for efficient photocatalytic hydrogen production. The hybrid nanosheets consist of Zn0.5Cd0.5S nanoparticles-core and OLC-shell structure, making Zn0.5Cd0.5S to be completely wrapped by carbon layers. Compared to pure Zn0.5Cd0.5S quantum dots (QDs) and nanosheets, the hybrid presents a large red shift in the light absorption edge at 550 nm and extended absorption over the longer wavelength range. A typical type II band alignment forms at Zn0.5Cd0.5S-OLC interface, together with the core-sheath 2D structure, greatly prompting the interfacial charge separation and transfer along the parallel and perpendicular directions of the nanosheets, finally leading to the improved H-2 generation rate of 10.8 mmol/g/h, exceeding the Zn0.5Cd0.5S nanosheets (6.4 mmol/g/h) and QDs (3.4 mmol/g/h). Further, the effect of the addition of OLC on the property of the hybrid nanosheets was also investigated. This work throws light on the improvement strategies for hydrogen production by morphology control and hetero-structure construction.