Facile preparation of PAN@Ag-Ag2O/TiO2 nanofibers with enhanced photocatalytic activity and reusability toward oxidation of As(III)

摘要

Visible light response PAN@Ag-Ag2O/TiO2 (PAN@AT) nanofibers with different mass ratios between Ag-Ag2O and TiO2 were synthesized via a facile electrospinning technique and pH-induced precipitation reaction. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscope analyses manifest the formation of Ag-Ag2O/TiO2 heterojunctions, and Ag-Ag2O/TiO2 nanoparticles are evenly distributed on PAN nanofibers. The fabricated nanofibers show a highly photocatalytic performance toward As(III) oxidation under visible light, and the conversion is 92.1% after 120-min reaction at pH 5.0 in the system of PAN@AT4. Furthermore, conversion of As(III) can retain 88.6% of the original activity after repeating four cycles, indicating the good recyclability of PAN@AT4 nanofibers. Quenching experiments and electron spin resonance spectra analysis further demonstrate that the predominate active species for As(III) oxidation by PAN@AT4 are h(+) and (OH)-O-center dot. The enhanced catalytic activity of PAN@AT4 is therefore ascribed to the formation of Ag-Ag2O/TiO2 heterojunctions on PAN surface and the efficient separation of photoinduced electron-hole pairs. This study provides a new material to oxidize reducing pollutants [such as As(III)] and also sheds light on the fabrication of recyclable photocatalysts.