Visible light response PAN@Ag–Ag 2 O/TiO 2 (PAN@AT) nanofibers with different mass ratios between Ag–Ag 2 O and TiO 2 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–Ag 2 O/TiO 2 heterojunctions, and Ag–Ag 2 O/TiO 2 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. The enhanced catalytic activity of PAN@AT4 is therefore ascribed to the formation of Ag–Ag 2 O/TiO 2 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.
In recent years, environmental pollution caused by volatile organic compounds (VOCs) has posed a great challenge to environmental protection. This first-attempt study provided a novel facile chemical precipitation-reduction method to construct Ag/Ag 2 O@TiO 2 (A/AO@TO) photocatalyst for the removal of gaseous toluene. The introduction of Ag in the presence of NaBH 4 with N 2 purging inhibited the passivation of Ag 2 O and thus enhanced the stability of A/AO@TO. A/AO@TO exhibited outstanding photocatalytic performance toward gaseous toluene under different light sources like UV light , simulated sunlight and natural light, which were 99.3%, 48.3% and 28.5%, respectively. The superior photocatalytic performance could be attributed to the synergy effect of p-n heterojunction between Ag 2 O and TiO 2 and the surface plasmon resonance (SPR) effect of Ag, which facilitate the separation of charge carriers and thus suppress the recombination rate of them, and enhance the light response. The active species like ·OH, ·O 2 − and h + were contributed to the excellent photocatalytic performance. The study provided a new method for the fabrication of A/AO@TO photocatalyst and introduce p-n scheme A/AO@TO as a feasible natural sunlight photocatalyst for further applications.
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