Solvothermal preparation spherical ZnS nano-photocatalyst and its photocatalytic activity

A series of ZnS photocatalysts were prepared by a solvothermal method with ethylene glyclo as the reaction medium and zninc acetate （Zn （CH₃COO）₂·2H₂O）and thiourea （ （NH₂）2CS）as the precursors. The effects of reaction temperature and time on the crystallnity ， surface area， optic adsorption and photocatalytic performance of the ZnS were investigated. The obtained ZnS samlpes were characterized by N₂ physical adsorption （BET）， scanning electron microscopy （SEM），X-ray diffraction （XRD），UV-vis diffuse reflectance spectra （UV-vis DRS）， and photoluminescence spectroscopy （PL）. The photocatalytic activity of the prepared samples was evaluated by photocatalytic degradation of different dyes under UV light （λ=254 nm） irradiation. The experimental results show that these photocatalysts prepared under solvothermal condition have good crystallinity and spherical morphology. ZnS photocatalyst prepared at 140 ℃ for 16 h shows the highest photocatalytic activity in decomposition of the dyes. After 5 hours ’ light irradiation， the degradation rates of the dyes of acid orange II， methyl orange， methylene blue， and rhodamine B are 91.49 %， 93.04 %， 64.63 % and 51.79 %， respectively. This high photocatalytic activity is mainly attributed to the good crystallnity ， big surface area， and less crystal defects of the ZnS prepared under the optimal condition.