Decomposition of nonionic surfactant on a nitrogen-doped photocatalyst under visible-light irradiation

• Published in: Applied catalysis. B, Environmental Vol. 55; no. 3; pp. 195 - 200
• Main Authors: Mozia, Sylwia, Tomaszewska, Maria, Kosowska, Beata, Grzmil, Barbara, Morawski, Antoni W., Kałucki, Kazimierz
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 10.02.2005
• Subjects: Ammonia; FT-IR study; Nitrogen doping; Nonionic surfactant; Titanium dioxide; Visible-light-active photocatalyst; Ammonia; Visible-light-active photocatalyst; Nitrogen doping; FT-IR study; Titanium dioxide; Nonionic surfactant
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2004.09.019

A visible-light-active N-containing TiO2 photocatalysts were prepared from crude amorphous titanium dioxide by heating amorphous TiO2 in gaseous NH3 atmosphere. The calcination temperatures ranged from 200 to 1000°C, respectively. UV–vis/DR spectra indicated that the N-doped catalysts prepared at temperatures <400°C absorbed only UV light (Eg=3.3eV), whereas samples prepared at temperatures ≥400°C absorbed both, UV (Eg=3.10–3.31eV) and vis (Eg=2.54–2.66eV) light. The chemical structure of the modified photocatalysts was investigated using FT-IR/DRS spectroscopy. All the spectra exhibited bands indicating nitrogen presence in the catalysts structure. The photocatalytic activity of the investigated catalysts was determined on a basis of a decomposition rate of nonionic surfactant (polyoxyethylenenonylphenol ether, Rokafenol N9). The most photoactive catalysts were those calcinated at 300, 500 and 600°C. For the catalysts heated at temperatures of 500 and 600°C Rokafenol N9 removal was equal to 61 and 60%, whereas TOC removal amounted to 40 and 35%, respectively. In case of the catalyst calcinated at 300°C surfactant was degraded by 54% and TOC was removed by 35%. The phase composition of the most active photocatalysts was as follows: (a) catalyst calcinated at 300°C—49.1% of amorphous TiO2, 47.4% of anatase and 3.5% of rutile; (b) catalyst calcinated at 500°C—7.1% of amorphous TiO2, 89.4% of anatase and 3.5% of rutile; (c) catalyst calcinated at 600°C—94.2% of anatase and 5.8% of rutile.