Enhanced photocatalytic performance of novel visible light-driven Ag-TiO₂/SBA-15 photocatalyst

Ag-TiO₂/SBA-15 composites were synthesized by two simple steps: firstly, TiO₂ was inserted into the pore of SBA-15 by hydrolysis method, and then Ag was doped on the surface of TiO₂/SBA-15 by the reduction of glucose. The as-prepared Ag-TiO₂/SBA-15 composites were thoroughly characterized by X-ray diffraction, transmission electron microscopy with energy dispersion X-ray spectrum, X-ray photoelectron spectroscopy, N ₂ adsorption-desorption isotherms, UV-vis diffuse reflectance spectra and photoluminescence spectra. The photocatalytic activity was evaluated by photodegradation of Rhodamine B (RhB) under visible light irradiation. The experimental results indicated that Ag-TiO₂/SBA-15 exhibited higher photocatalytic activity than that of P25 and TiO₂/SBA-15, and could keep good stability. The significant enhancement in photodegradation activity might be ascribed to the combined effects, including enhanced reactant adsorption by the mesoporous structure of SBA-15, well distribution of TiO ₂ in the pores of SBA-15, and reduced electron-hole recombination rates due to Ag doping. In addition, a possible mechanism for the photodegradation process was proposed on the basis of active species scavenging experiments.