Zn0.3Cd0.7S nanorods loaded with noble-metal-free Ni3C co-catalyst enhancing photocatalytic hydrogen evolution

Abstract

ZnCdS, a kind of ternary transition metal sulfides, which have tunable absorption in the visible region of solar energy and proper negative conduction band position, is considered as a compatible candidate for effective photocatalytic hydrogen production. Recently, some of the low-cost metal carbides have been demonstrated experimentally to be an excellent substitution of noble metal working as co-catalyst with photocatalysts in H2-evolution process to improve the photocatalytic activity. In this study, Ni3C nanoparticles (NPs) were used as co-catalysts to modify Zn0.3Cd0.7S nanorods during the photocatalytic H2 evolution under visible light irradiation for the first time. The photocatalytic H2 evolution rate of Zn0.3Cd0.7S nanorods under visible light irradiation (517.4 μmolg−1 h−1) is improved for more than six times by loading a suitable amount of Ni3C NPs as co-catalyst (3310.1 μmolg−1 h−1). The structure, composition, and morphology of the Ni3C loaded Zn0.3Cd0.7S nanorods are characterized by XRD, XPS, VSM, SEM, and HRTEM. The effects of co-catalyze with Ni3C on the absorption of visible light, electron-hole separation, and H2-evolution kinetics are investigated. It is believed that loading with Ni3C mainly increases the separation of electron-hole pairs in the photocatalyst, it also reduces the band-gap of the photocatalyst by lowing the CBM position, and improving the kinetics for H2 evolution.