Au NPs@MoS2 Sub-Micrometer Sphere-ZnO Nanorod Hybrid Structures for Efficient Photocatalytic Hydrogen Evolution with Excellent Stability.

Abstract

MoS2 shows promising applications in photocatalytic water splitting, owing to its uniquely optical and electric properties. However, the insufficient light absorption and lack of performance stability are two crucial issues for efficient application of MoS2 nanomaterials. Here, Au nanoparticles (NPs)@MoS2 sub-micrometer sphere-ZnO nanorod (Au NPs@MoS2 -ZnO) hybrid photocatalysts have been successfully synthesized by a facile process combining the hydrothermal method and seed-growth method. Such photocatalysts exhibit high efficiency and excellent stability for hydrogen production via multiple optical-electrical effects. The introduction of Au NPs to MoS2 sub-micrometer spheres forming a core-shell structure demonstrates strong plasmonic absorption enhancement and facilitates exciton separation. The incorporation of ZnO nanorods to the Au NPs@MoS2 hybrids further extends the light absorption to a broader wavelength region and enhances the exciton dissociation. In addition, mutual contacts between Au NPs (or ZnO nanorods) and the MoS2 spheres effectively protect the MoS2 nanosheets from peeling off from the spheres. More importantly, efficiently multiple exciton separations help to restrain the MoS2 nanomaterials from photocorrosion. As a result, the Au@MoS2 -ZnO hybrid structures exhibit an excellent hydrogen gas evolution (3737.4 μmol g-1 ) with improved stability (91.9% of activity remaining) after a long-time test (32 h), which is one of the highest photocatalytic activities to date among the MoS2 based photocatalysts.