Design and fabrication of ternary Au/Co3O4/ZnCdS spherical composite photocatalyst for facilitating efficient photocatalytic hydrogen production

Abstract

Promoting efficient carrier separation and transfer can largely enhance photocatalytic performance and inhibit photo-corrosion. In this work, ZnCdS (ZCS) microspheres were obtained by a self-assembly strategy, and the Au/Co₃O₄/ZCS composites were synthesized by a modified photo-deposition method (loading Co₃O₄ and Au onto the surface of ZnCdS). The synergistic effect between the S-scheme heterojunction (Co₃O₄/ZCS) and Schottky junction (Au/ZCS) can effectively promote the generation and separation of photoelectrons and holes, thus enhancing the photocatalytic activity. Under visible light, the efficient photocatalysts showed hydrogen production activities up to 2525 μmol g⁻¹ h⁻¹, which is 2.24 times higher than that of Co₃O₄/ZCS and 6.92 times higher than that of pure ZnCdS. DFT calculations indicate that the built-in electric field between Co₃O₄/ZCS provides the driving force for efficient electron-hole separation, and the Au nanoparticles (NPs) act as electron collectors at the interface of ZnCdS to capture the electrons, which effectively prolongs the lifetime of photoelectrons and further enhances the photocatalytic hydrogen production activity.