title: Photocatalytic removal of NO and NO2 using titania nanotubes synthesized by hydrothermal method.
abstract: In this study, the photocatalysts of titania nanotubes (TNTs) were synthesized at different calcination temperatures using commercial Degussa TiO2 (P25) as a precursor. The materials were then characterized by BET, SEM, TEM, and XRD analyses. The photocatalytic reactions with NO and NO2 under UV-A irradiation were both performed. The results showed that the photocatalytic reaction rate of NO was much faster than that of NO2, and the conversion of NO2 to nitrate was the rate-limiting step for photocatalytic removal of NOx if the nitrate produced cannot be removed continuously from the photocatalyst surface. For TNTs calcined at different temperatures, a significant enhancement was observed on the total NOx removal efficiency by TNT calcined at 500°C for both NO and NO2 photocatalytic reaction, which could be attributed to its high anatase crystallinity as well as high surface area. These two factors affect primarily on the NO2 conversion step in which the high anatase crystallinity could be responsible for the high efficiency at the beginning, while the high surface area could be accounted for retaining this high efficiency from nitric acid poisoning during the test period.
authors: Institute of Environmental Engineering, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan, Chinese Taipei. Electronic address: nhathuy1017@yahoo.com.
authors: Nhat Huy
authors: NH
authors: Nguyen
authors: Institute of Environmental Engineering, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan, Chinese Taipei. Electronic address: hlbai@mail.nctu.edu.tw.
authors: Hsunling
authors: H
authors: Bai
mesh_terms: D000327:Adsorption; D000393:Air Pollutants / Q000737:chemistry; D002384:Catalysis; D006358:Hot Temperature; D008855:Microscopy, Electron, Scanning; D043942:Nanotubes / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D009609:Nitrous Oxide / Q000737:chemistry*; D055668:Photochemical Processes; D014025:Titanium / Q000737:chemistry*
chemical_list: D000393:Air Pollutants; D009569:Nitric Oxide; D014025:Titanium; D009609:Nitrous Oxide
keywords: TNTs; TiO(2); environmental photocatalysis; indoor air pollution control; nitrogen oxides