Silver-modification of ZnO thin films deposited on Zn-electroplated Cu substrate by thermal shock method for the enhanced photocatalytic performance

Abstract

Ag-modified ZnO thin films on Zn-electroplated Cu substrate with different Ag-contents were prepared via a simple sol–gel spin-coating procedure followed by a thermal shock method with AgNO3, and then characterized by XRD, Raman, FTIR, FESEM, EDX, and UV-visible absorption spectroscopy. Their photocatalytic performance was evaluated by the degradation of methylene blue. Due to the sol–gel spin-coating process, the film was successfully immobilized on mechanically robust Zn/Cu plates, making it promising for applications in harsh practical conditions and facilitating recovery. When our ZnO thin films were surface-modified with AgNO3 at 1 and 2 mol%, they exhibited the best photocatalytic activity under UVA light and visible light, respectively, which can be explained by the appearance of maze-like architecture on their surface with vertical ZnO walls, surface defects and metallic silver nanoparticles. However, when the Ag-content was increased to 3 mol%, the maze-like structure collapsed, leading to decreases in photocatalytic performance.

Keywords

• ZnO thin film
• Ag-modification
• sol–gel spin-coating method
• thermal shock method
• photocatalysis