Synthesis of visible light responsive ZnO-ZnS/C photocatalyst by simple carbothermal reduction

A new visible light responsive ZnO-ZnS/C photocatalysts have been successfully synthesized by a simple heat-treating procedure using ZnSO4 as single precursor for the first time. The resultant samples were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy and BET surface area measurement. The results showed that the ZnO-ZnS/C catalysts were directly formed by thermal decomposition of ZnSO4 impregnated on the activated carbon at high temperature under open atmospheric conditions. Here, a possible growth mechanism of the coupled ZnO-ZnS/C photocatalysts was proposed. Activated carbon played both reducing agent and support role in formation of ZnO-ZnS/C catalysts. The photocatalytic activities of catalysts were investigated by degrading reactive brilliant blue K-3R under visible light irradiation. The synthesized catalysts showed excellent photocatalytic activity compared with ZnO/C and pure ZnO, which is ascribed to the formation of ZnO-ZnS heterojunctions in catalysts. Furthermore, influences of preparation conditions on photocatalytic activity of the catalysts have been investigated. (C) 2010 Elsevier B.V. All rights reserved.