Enhanced Hydrogen Production over C-Doped CdO Photocatalyst in Na2S/Na2SO3 Solution under Visible Light Irradiation

The C-doped CdO photocatalysts were simply prepared by high-temperature solid-state process. The as-prepared photocatalysts were characterized by X-ray powder diffraction (XRD), diffuse reflectance spectroscopy (UV-Vis DRS), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the carbon was doped into CdO, resulting in the red-shift of the optical absorption of CdO. The photocatalytic behavior of CdO and C-doped CdO was evaluated under the visible light irradiation by using the photocatalytic hydrogen evolution as a model reaction. The C-doped CdO photocatalysts had higher photocatalytic activity over parent CdO under visible light irradiation. The results indicated that the H-2 production was due to the existence of CdS and the enhancement of visible light photocatalytic activity of H-2 production was originated from the doping of carbon into the CdO lattice. The probably reaction mechanism was also discussed and proposed.