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

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.