Design of H3PW12O40/TiO2 and Ag/H3PW12O40/TiO2 film-coated optical fiber photoreactor for the degradation of aqueous rhodamine B and 4-nitrophenol under simulated sunlight irradiation

Abstract In order to improve sunlight-energy utilization efficiency of the photocatalyst for the degradation of organic pollutants in wastewater, a novel photoreactor that comprised H 3 PW 12 O 40 /TiO 2 or metallic Ag deposited H 3 PW 12 O 40 /TiO 2 film-coated optical fiber bundles was designed by the steps of sol–gel, hydrothermal treatment, photoreduction, and dip coating. The H 3 PW 12 O 40 /TiO 2 or Ag/H 3 PW 12 O 40 /TiO 2 film exhibited anatase phase, mesoporosity, and charge transfer band in the range of 200−400 nm or 200−800 nm. The photocatalytic activity of the H 3 PW 12 O 40 /TiO 2 and Ag/H 3 PW 12 O 40 /TiO 2 film-coated optical fibers was evaluated by the degradation of rhodamine B and 4-nitrophenol in aqueous solutions under the irradiation of commercial Xe lamp and self-made solar simulator (320 nm  λ 3 PW 12 O 40 /TiO 2 or Ag/H 3 PW 12 O 40 /TiO 2 film in comparison of TiO 2 film was obtained and explained in terms of the synergistic photocatalytic effect between Keggin unit and TiO 2 as well as surface plasmon resonance effect of metallic Ag; and considerably high photocatalytic activity of the H 3 PW 12 O 40 /TiO 2 and Ag/H 3 PW 12 O 40 /TiO 2 film in the optical fiber photoreactor is explained by the superior light-energy utilization of the catalyst in the optical-fiber reactor. Finally, the reusability of the catalyst film was evaluated through six consecutive catalytic runs.