Enhanced visible Light-Driven photocatalytic hydrogen evolution and stability for noble Metal-Free MoS2/Zn0.5Cd0.5S heterostructures with W/Z phase junctions

Abstract

A series of composite heterojunction-MoS2/Zn0.5Cd0.5S photocatalysts free of noble metal ions was prepared using a simple hydrothermal method. The X-ray diffraction spectra of the MoS2/Zn0.5Cd0.5S composites exhibit three strong intensive peaks, thereby explaining the existence of wurtzite (CdS) and zinc blende (ZnS) in the form of the wurtzite/zinc-blende phase junctions. Microstructural studies indicate that the sample displays a typical cubic crystal structure and that the MoS2 with flower-like structure uniformly wraps the granular Zn0.5Cd0.5S. X-ray photoelectron, Fourier transform infrared, and UV–Vis diffuse reflectance spectroscopic methods confirm that the heterojunction, which possesses outstanding photoresponse ability, is constructed between Zn0.5Cd0.5S nanoparticles and MoS2 nanoflowers. The fluorescence spectroscopy, surface photocurrent spectroscopy, and electrochemical studies indicate that Zn0.5Cd0.5S nanoparticles with specific amount of MoS2 nanoflowers can effectively suppress the recombination of photoinduced charge carriers of the composites. Therefore, pristine Zn0.5Cd0.5S nanoparticles loaded with 3%MoS2 exhibit optimum performance of hydrogen production (388.2 μmol/h), which is 1.3 times that of pristine Zn0.5Cd0.5S nanoparticles. A plausible mechanism for enhanced photocatalysis is provided in terms of the heterojunction assisted effective separation of charge carriers that are generated by irradiation.