Synthesis, optical, photocatalytic, and electrochemical studies on Ag2S/ZnS and ZnS/Ag2S nanocomposites

Novel Ag2S/ZnS and ZnS/Ag2S nanocomposites were synthesized by a simple chemical method in air. Different morphologies were obtained for Ag2S/ZnS nanocomposites annealed at different temperatures. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible absorption, and photoluminescence (PL) spectroscopy. Thermal stability and phase transition of the sample were studied by TG-DTA. Compared the PL spectra of Ag2S/ZnS at 640 nm, it was significantly red shifted from 640 to 670 nm for reversed ZnS/Ag2S nanocomposites. The band gaps of nanocomposites were lying between 2.25 and 2.55 eV range. It has been found that as-synthesized powder has excellent photocatalytic activity toward degradation of methylene blue (MB) under visible light and electrochemical activity, indicating that Ag2S/ZnS and ZnS/Ag2S nanocomposites can play an important role as semiconductor photocatalyst and energy storage applications.