Fabrication of Hollow Mesoporous CdS@TiO2@Au Microspheres with High Photocatalytic Activity for Hydrogen Evolution from Water under Visible Light

Hollow mesoporous CdS@TiO2@Au microspheres as a photocatalyst have been successfully synthesized by γ-irradiation deposition of Au nanoparticles (NPs) on the double shell of hollow CdS@TiO2 microspheres, which are prepared via the “hard core template” approach combining with calcination and solvothermal reaction. The morphology, structure, and properties of the as-prepared hybrid photocatalyst have been characterized by TEM, XRD, XPS, N2 adsorption–desorption, UV–vis DRS, PL, and photoelectrochemical measurements. The results show that the hollow mesoporous double-shell structure is formed with a fluffy TiO2 coating on the surface of the CdS shell composed of stacked CdS NPs. This ternary hybrid photocatalyst exhibits excellent photocatalytic activity for hydrogen evolution and stability under visible-light illumination, which is attributed to the unique ternary hollow mesoporous double-shell heterostructure that may extend the light responsive region, enhance the light-harvesting efficiency, prevent the direct contact between the CdS shell and O2 and H2O, facilitate mass transfer, reduce the recombination rate of charge carriers, and promote the efficiency of water splitting H2 evolution ultimately. The photocatalytic hydrogen generation rate (1720 μmol·g–1·h–1) of the hollow CdS@TiO2@Au microspheres is 2.37 and 12.7 times higher than those of hollow CdS@TiO2 and CdS microspheres, respectively. The loading amount of Au NPs also influences the photocatalytic hydrogen evolution activity of the ternary photocatalyst. Our work expands the application of hybrid hollow microsphere photocatalysts in photocatalytic hydrogen generation by the rational design for enhancing photocatalytic activity under visible light.