Synthesis and characterization of ZnS-TiO2 photocatalyst and its excellent sun light driven catalytic activity

The different wt% of ZnS loaded TiO2 (ZnS-TiO2) catalysts were successfully synthesized by precipitation cum sol-gel method and used for degradation of phenol dye, Phenol red sodium salt (PRSS) under natural sun light. Highly efficient 10.7 wt% of ZnS-TiO2 was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectrum (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL) and BET surface area measurements. ZnS-TiO2 is found to be more efficient than bare TiO2, TiO2-P25 and ZnS at pH 6.5 for the mineralization of PRSS dye. The effects of operational parameters such as the amount of photocatalyst and dye concentration have been analyzed. The mineralization of PRSS dye has been confirmed by chemical oxygen demand (COD) measurements. A dual mechanism has been proposed for the degradation of PRSS under solar light. This catalyst is found to be reusable.