Synthesis and photocatalytic activity of hollow CdS microspheres
Traditionally, hollow CdS spheres can be prepared via a template-free hydrothermal process that requires higher Cd2+-to-S2− molar ratios with lower yields. In this research, we report a facile and template-free alcohol thermal approach for the synthesis of high-surface area hollow CdS microspheres at a 1 : 1 Cd2+-to-S2− molar ratio. The effects of the precursor chemical concentrations, reaction temperature and reaction time indicate that the formation of CdS hollow nanospheres was due to the Ostwald ripening mechanism. The stoichiometric Cd2+-to-S2− ratio promotes higher production of hollow CdS particles. The activities of the prepared CdS samples are evaluated based on the visible light photocatalytic degradation of methylene blue (MB) solution. Results indicate that the MB photocatalytic degradation rate is linearly related to the surface area of CdS particles with the highest photocatalytic activity for the hollow CdS microsphere samples having the highest surface area.