Preparation of Pt/TiO2 hollow nanofibers with highly visible light photocatalytic activity

摘要

The Pt/TiO2 hollow nanofibers (HNFs) as a photocatalyst have been successfully prepared by a uniaxial electrospinning method combined with photo-deposition. The as-synthesized photocatalysts were characterized by TEM, XRD, SAED, EDX, XPS, N-2 adsorption-desorption, and UV-vis DRS. The TiO2 HNFs were composed of an anatase-rutile mixed phase, with the ratio of similar to 70:30. The band gap of TiO2 HNFs decreased from 3.09 down to 2.77 eV with 2 wt.% Pt loading, this led to an enhanced photocatalytic performance under visible light. By evaluating the degradation of azo dye Orange II, the pseudo-first-rate constant (kappa) of Pt/350-TiO2 HNFs system was 0.0069 min(-1), which was 11.5 and 3.63 times higher than for TiO2 HNFs and Pt/P25, respectively. The main factors affecting the photocatalytic activity were further investigated, these included the loading amount of Pt, the calcination temperature of TiO2 HNFs, the pH of initial solution and the light source. The results of repeated use of the Pt/TiO2 HNFs demonstrated that the photocatalysts exhibited an excellent stability even after ten cycles. The possible degradation mechanism was also studied. It was shown that center dot O-2(-) radicals were the main reactive oxygen species for the degradation of Orange II. (C) 2016 Elsevier B.V. All rights reserved.