A comparative study of photocatalytic activity of ZnS photocatalyst for degradation of various dyes

A simple chemical precipitation method is used to synthesize the cubic phase of ZnS nanoparticles. The crystal structure, phase purity, surface morphology, optical and photo-luminescence properties, and photocatalytic activity of ZnS nanoparticles were studied using X-ray diffraction (XRD), fourier transform infrared (FTIR) spectra, Raman spectrometer, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), UV-vis spectrophotometer, fluorescence spectrophotometer and 721 spectrophotometer. XRD, FTIR, Raman and XPS analysis indicates that the ZnS nanoparticles has a cubic phase with the cell parameter a = 5.406 Å without the presence of any other impurities. SEM image shows that the average particle size of ZnS nanoparticles is about 40 nm. Optical properties and photoluminescence experiment confirmed that the Eg value is found to be 3.21 eV and the emission spectra are made up of four emission bands at 345, 408, 444 and 510 nm under excitation wavelength at 290 nm. Photocatalytic experiment results indicate that the pure ZnS nanoparticles exhibits an obviously enhanced photocatalytic activity for degradation MO, and MR dyes than degradation MB, and XO dyes due to the ZnS nanoparticles can easily degradation the NN bonds. Based on the electrochemical measurement and photocatalytic experiment, a possible photocatalytic mechanism for degradation of various dyes in presence of the ZnS nanoparticles are analyzed.