Morphology-Controlled Synthesis of Zn<sub>x</sub>Cd<sub>1-x</sub>S Solid Solutions: An Efficient Solar Light Active Photocatalyst for the Degradation of 2,4,6-Trichlorophenol

Abstract

Zn x Cd 1−x S solid solutions with controlled morphology have been successfully synthesized by a facile solution-phase method. The prepared samples were characterized by X-ray powder diffraction (XRD), UV-vis diffuse reflectance spectra, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic activity of Zn x Cd 1−x S was evaluated in the 2,4,6-trichlorophenol (TCP) degradation and mineralization in aqueous solution under direct solar light illumination. The experiment demonstrated that TCP was effectively degraded by more than 95% with 120 min. The results show that ZnS with Cd doping (Zn x Cd 1−x S) exhibits the much stronger visible light adsorption than that of pure ZnS, the light adsorption increasing as the Cd 2+ doping amount. These results indicate that Cd doping into a ZnS crystal lattice can result in the shift of the valence band of ZnS to a positive direction. It may lead to its higher oxidative ability than pure ZnS, which is important for organic pollutant degradation under solar light irradiation. Furthermore, the photocatalytic activity studies reveal that the prepared Zn x Cd 1−x S nanostructures exhibit an excellent photocatalytic performance, degrading rapidly the aqueous 2,4,6-trichlorophenol solution under solar light irradiation. These results suggest that Zn x Cd 1−x S nanostructure will be a promising candidate of photocatalyst working in solar light range.