CdS/Ag2S/g-C3N4 ternary composites with superior photocatalytic performance for hydrogen evolution under visible light irradiation

Abstract

CdS/Ag₂S/g-C₃N₄ ternary composites as photocatalysts with different amounts of Ag₂S were successfully synthesized through a simple chemical deposition method. These photocatalysts were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) mapping and X-ray photoelectron spectroscopy (XPS) to obtain the information of the structure and composition. Compared with the pure samples and binary composites, CdS/Ag₂S/g-C₃N₄ ternary composites showed enhanced hydrogen production activities, and the maximum hydrogen production rate of CdS/Ag₂S(2%)/CN is about 1020.54 μmol g⁻¹ h⁻¹ in Na₂S–Na₂SO₃ solution. Based on the photoluminescence and electrochemical results, the improved photocatalytic activity could be attributed not only to the synergic effect of ternary components in the composite, but also to the introduction of Ag₂S that provided abundant active sites for H₂ production. A possible mechanism was investigated in detail.