(335b) The Photocatalytic Activity Of ZnO/ZnS Core/Shell Particles For Methyl Orange

The photocatalytic activity of ZnO/ZnS core/shell particles for methyl orange

                                                                            Wenjiang Li^*a, Ge Song^a, Minfang Chen^a

Abstract: Recently, many novel properties of ZnO have been developed not only by the impurity doping but also through the surface modification [1]. A heterostructure formed by ZnO and another semiconductor can present a highly efficient photoelectric effect in the solar cells [2,3]. As is well known, ZnS with wide band gap also attracts much interest in photocatalysts, photoconductors, optical sensors, electroluminescent materials [12]. The band gap of ZnS (3.68eV) is larger than that of ZnO, and theoretical calculations and experimental results have demonstrated that the combination of these two semiconductors could yield a novel composite with the photo excitation threshold energy lower than those of the individual components [4]. In this paper, the novel spherical ZnO/ZnS core/shell particles were obtained after sulfurizing ZnO spheres by Na₂S. The pure spherical ZnO particles were firstly synthesized via a simple mild solvothermal approach by the assistance of diethylene glycol. Then, the partial ZnO molecules on the surface of the ZnO spheres were converted to ZnS molecules in the presence of S^2- ionsunder hydrothermal condition, and finally forming ZnS shell structure over the surface of ZnO spheres. The thickness of the ZnS shell is adjustable by controlling the sulfuration process of as-synthesized ZnO template. The photocatalytic activity of the ZnO/ZnS core/shell composite was evaluated by monitoring methyl orange degradation as the probe reaction.