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

Synopsis: A sustainable approach for the synthesis of noble-metal-free MoS 2 /Zn 0.5 Cd 0.5 S heterostructures with W/Z phase junctions with enhanced visible-light-driven photocatalytic hydrogen evolution and stability is reported. [Display omitted] • The noble-metal-free MoS 2 /Zn 0.5 Cd 0.5 S with W/Z phase junctions were prepared successfully. • Appropriate MoS 2 modification can enhance the separation efficiency of the charge carriers. • The 3%MoS 2 /Zn 0.5 Cd 0.5 S showed optimal visible-light photocatalytic hydrogen production. • The ESR spectra indicated that O 2 – and h+ played a major role during the degradation process. • The enhanced photocatalysis ascribed to interfacial optimization of double heterojunction. A series of composite heterojunction-MoS 2 /Zn 0.5 Cd 0.5 S photocatalysts free of noble metal ions was prepared using a simple hydrothermal method. The X-ray diffraction spectra of the MoS 2 /Zn 0.5 Cd 0.5 S 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 MoS 2 with flower-like structure uniformly wraps the granular Zn 0.5 Cd 0.5 S. 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 Zn 0.5 Cd 0.5 S nanoparticles and MoS 2 nanoflowers. The fluorescence spectroscopy, surface photocurrent spectroscopy, and electrochemical studies indicate that Zn 0.5 Cd 0.5 S nanoparticles with specific amount of MoS 2 nanoflowers can effectively suppress the recombination of photoinduced charge carriers of the composites. Therefore, pristine Zn 0.5 Cd 0.5 S nanoparticles loaded with 3%MoS 2 exhibit optimum performance of hydrogen production (388.2 μmol/h), which is 1.3 times that of pristine Zn 0.5 Cd 0.5 S 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. [ABSTRACT FROM AUTHOR]