Fabrication of PAN@TiO2/Ag nanofibrous membrane with high visible light response and satisfactory recyclability for dye photocatalytic degradation

Although TiO 2 -based photocatalysts have exhibited a great potential for degradation of organic pollutants, it is still necessary to simultaneously enhance their visible-light-driven photocatalytic efficiency and physical recyclability. Herein, highly efficient, visible-light-driven photocatalytically active, and recyclable nanofibrous membranes with thin TiO 2 /Ag heterojunction layer are prepared using electrospun polyacrylonitrile (PAN) nanofibrous membrane as the substrate. By regulating the concentration and hydrolysis process of Ti precursors, TiO 2 nanoparticles steadily grow on the PAN nanofibers with high-specific surface area to form a continuous mesoporous shell with the thickness of 20   nm for efficient degradation of organic pollutants. Furthermore, to form a stable heterojunction structure, Ag nanoparticles are deposited on the TiO 2 surface by using dopamine as a binder and reductant. The presence of Ag nanoparticles leads to an obvious red-shift from 380   nm to 490   nm, which improves the utilization efficiency of visible light, and reduces the electron/hole recombination rate simultaneously. The resulting PAN@TiO 2 /Ag membranes hold enhanced photocatalytic activity for methylene blue degradation within 1   h under visible light irradiation, and satisfactory recyclability, which endow them with a great potential for adsorption and photocatalytic applications.