Hybridization of Cd0.2Zn0.8S with g-C3N4 nanosheets: a visible-light-driven photocatalyst for H2 evolution from water and degradation of organic pollutants

Abstract

Novel visible-light-driven Cd_0.2Zn_0.8S/g-C₃N₄ inorganic–organic composite photocatalysts were synthesized by a facile hydrothermal method. The prepared Cd_0.2Zn_0.8S/g-C₃N₄ composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible diffuse reflection spectroscopy (DRS), photoluminescence (PL) spectroscopy and photoelectrochemical (PEC) experiments. Under visible-light irradiation, Cd_0.2Zn_0.8S/g-C₃N₄ photocatalysts displayed a higher photocatalytic activity than pure g-C₃N₄ and Cd_0.2Zn_0.8S for hydrogen evolution and degradation of pollutants, and the optimal g-C₃N₄ content was 20 wt%. The optimal composite showed a hydrogen evolution rate of 208.0 μmol h⁻¹. The enhancement of the photocatalytic activity should be attributed to the well-matched band structure and intimate contact interfaces between Cd_0.2Zn_0.8S and g-C₃N₄, which lead to the effective transfer and separation of the photogenerated charge carriers. Furthermore, the Cd_0.2Zn_0.8S/g-C₃N₄ photocatalysts showed excellent stability during photocatalytic hydrogen evolution and degradation of pollutants.