Photocatalytic properties of polydopamine-modified Ag NP/TiO2 porous nanofibers prepared by electrospinning

Abstract

Polydopamine-modified Ag/TiO₂ porous nanofibers (PDA-Ag/TiO₂ porous NFs) were successfully prepared as a composite catalyst via a simple electrospinning process combined with an impregnation method. It was found that the PDA-Ag/TiO₂ porous NFs present a corn-like, coarse, porous structure where the TiO₂ NFs look like corn cobs and the Ag nanoparticles (NPs) act as corn kernels. In our research, carbon nanotubes (CNTs) were embedded during the original spinning as pores were formed using electrospinning. After calcination, the loss of the CNTs left a lot of holes in the internal structure of the TiO₂ NFs that made the specific surface area increase by about 30 percent compared to the pure TiO₂ NFs. Ag NPs embedded in the TiO₂ NFs could prevent the recombination of electron–hole pairs generated from photocatalysis and could transfer the captured electrons to participate in the photocatalysis reaction process. The PDA which wrapped the TiO₂ NFs homogeneously could adsorb organic matter and promote the spatial separation of photogenerated charges. The higher photocatalytic efficiency demonstrated a synergy between the Ag NPs and PDA with PDA playing the role of the gripper to capture organic molecules, and the Ag NPs doped in the TiO₂ NFs acting as the electron conveyer which could restrain the recombination of electron–hole pairs. The new composite catalyst has potential application in cleaning up organic pollutants.