Band gap tuning of ZnO/In₂S₃ core/shell nanorod arrays for enhanced visible-light-driven photocatalysis

Abstract

We report an efficient and environmentally benign one-dimensional ZnO/In₂S₃ core/shell nanostructure to be used as a photocatalyst to overcome the drawback of low photocatalytic efficiency brought by electron–hole recombination and narrow photoresponse range. In₂S₃ nanoparticles were successfully grown on the ZnO nanorods by the surface functionalization method using citric acid as a surface-functionalizing agent. The photocatalytic activity under visible light to degrade rhodamine B (RhB) was enhanced by these core/shell nanostructures due to the formation of heterojunctions, which prolong the separation of photogenerated electrons and holes. The photocatalytic degradation of RhB dye was found to be 83.7, 2.7, and 35.0% for the ZnO/In₂S₃ core/shell nanorod arrays, ZnO nanorods, and In₂S₃ nanoparticles, respectively, under visible light irradiation. Photoconductivity studies showed a 6-fold enhancement in photocurrent (compared to the dark current) for the core/shell nanorod arrays. Moreover, these core/shell nanostructures could be reused for degradation of RhB during a three-cycle experiment without significant decrease in the photocatalytic activity which is very important for these ZnO/In₂S₃ core/shell nanorod arrays to be of practical use in environmental applications.