Controllable synthesis of Ag@TiO2 heterostructures with enhanced photocatalytic activities under UV and visible excitation

Abstract

The heterostructure of Ag doped-TiO₂ has been fabricated through the facile synthesis of electrospinning technique and hydrothermal reaction. During the hydrothermal process, the concentrations of reactants play a significant role in controlling the size and load of Ag NPs on the surface of the TiO₂ fibers. After that, the nanoheterostructures of Ag@TiO₂ were characterized by Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HRTEM), X-ray Diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Simultaneously, diffuse reflectance was used to investigate the visible light adsorption ability. Surface modification by Ag rendered visible light-induced photocatalytic activity to the TiO₂ fibers. Rhodamine B (RhB) was employed as a representative dye pollutant to evaluate the photocatalytic activity of the Ag/TiO₂ samples. The results indicated that the heterojunction structure of Ag/TiO₂ exhibited higher degradation efficiency than the pure TiO₂ fibers. Furthermore, we also investigated the photocatalytic performance under visible-light, which exhibited a significant increase in degradation efficiency. Additionally, the proposed mechanism for the enhanced photocatalytic activity of TiO₂ fibers by deposited-Ag particles was proposed.