Enhanced solar and visible light photocatalytic activity of In2S3-decorated ZnO nanowires for water purification

摘要

In a previous paper, we have demonstrated a facile and low-cost synthesis of ZnO/In2S3 core/shell nanowires (NWs) on indium tin oxide substrates by a two-step electrochemical method. The main objective of the present study was to demonstrate the potentiality of this system in visible and solar photocatalysis for water treatment applications. The morphological, structural and photophysical properties of the core/shell NWs were investigated through TEM, XRD, Raman, wettability and UV-vis absorption. The photocatalytic activity of the ZnO/In2S3 core/shell NWs was investigated under solar light and visible light irradiation using mainly methylene blue in aqueous solutions. The influence of the materials (In2S3 shell thickness) as well as the operating parameters, including the nature and the intensity of the incident light irradiation (visible and solar), the nature and the concentration of the pollutants (methylene blue, methyl orange, and salicylic acid), and the pH of the solution were examined. The hydroxyl radicals involved in the photodegradation process were also addressed at different excitation wavelengths. The experimental results pointed out that the pollutants can be degraded completely within 120 min by the ZnO/In2S3 core/shell and their photodegradation rate were 5 times faster than those of pure ZnO nanowires. The reusability test highlighted that the ZnO/In2S3 NWs arrays still maintained high photocatalytic activity over five cycles. The as-synthesized ZnO/In2S3 core/shell provide a facile, low cost, large photocatalytic efficiency, and high reusability, which shall be also promising in many related areas, such as solar energy conversion, water splitting, and energy storage.