Visible light-driven photocatalytic dye degradation under natural sunlight using Sn-doped CdS nanoparticles.

Herein, cadmium sulfide (CdS) nanoparticles (NPs) and different concentrations (1-5 and 10 wt %) of Sn-doped CdS NPs were prepared by a chemical precipitation method using PVP as a capping agent. The synthesized NPs were characterized using various characteristic techniques such as XRD, SEM, TEM, Raman spectroscopy, UV-Vis, and photoluminescence to investigate structural, morphological, and optical properties. Optical band gap of CdS has been tuned by substitution of Sn with different concentrations. Pure CdS and Sn-doped CdS NPs were used for the photocatalytic degradation of methylene blue (MB) dye under direct sunlight irradiation. The photocatalytic activity of the Sn-doped CdS NPs is attributed to the interface actions between Sn and CdS, which significantly decreases the recombination of a photogenerated electron-hole pair. The degradation efficiencies were found to be 91.39% and 97.56% within 180 min for pure CdS and Sn-doped CdS NPs, respectively. Among the catalysts, 4% Sn-doped CdS NPs exhibit best photocatalytic degradation efficiency after 180 min of irradiation.