Enhanced photocatalytic activity and stability of interstitial Ga-doped CdS: Combination of experiment and calculation

Abstract

Herein, a series of Ga-doped CdS photocatalysts are successfully prepared by simple solvothermal method using absolute ethyl alcohol as only reaction solvent. The samples have been characterized by X-ray diffraction, scanning electron microscope, UV–vis diffuse reflectance spectrum, X-ray photoelectron spectroscopy and electrochemical measurements. Their photocatalytic activity has been evaluated by the photocatalytic degradation of rhodamine B (RhB) under simulated visible-light irradiation. It is found that the prepared samples are interstitial Ga-doped CdS, which has never been reported before. The photocatalytic activity of Ga-doped CdS with molar ratio of Ga:Cd=1:50 for RhB degradation can be enhanced by 114% in comparison with that of pure CdS under same reaction conditions. All of the data based on theoretical calculation and experiment indicate that Ga ion doped into the interstice of crystal lattice in CdS can not only lower the valence band position but also decrease the formation energy of the CdS samples. What is more, Ga ion doping can widen the valence band of CdS semiconductor, which is quite beneficial for the separation of photo-generated carriers. As a result, the Ga-doped CdS not only has improved photocatalytic activity for the degradation of pollutant pollutants but also has enhanced stability under visible-light irradiation. In a word, Ga-doped CdS will be a promising photocatalyst with richly potential application prospect under solar light.