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2 Polish Journal of Chemical Technology

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Preparation of the TiO2 photocatalyst using pressurized ammonia

Wawrzyniak B., Janus M., Grzmil B., Morawski A. W.

Polish Journal of Chemical Technology

2007

Vol. 9, nr 1

51-56

The industrial hydrated amorphous titanium dioxide (TiO2 ź xH2O) was modified by treatment inside a chemical reactor under elevated pressure at low temperatures for 4 hours in an ammonia atmosphere. On the basis of the FTIR/DRS analysis the presence of nitrogen was confirmed. The XRD patterns of all of the catalysts exhibit mainly the diffraction lines of anatase phases. The photocatalytic activity of the modified photocatalysts was determined and compared to TiO2-P25 (Degussa, Germany). The high rate of phenol and dye degradation was obtained for the catalysts modified at 180°/5atm. TiO2-P25 showed similar activity in phenol decomposition like TiO2-15bar, whereas it was more active in dye decomposition.

TiO2-nitrogen doped for both the UV and Visible light photocatalysis

Morawski A. W., Janus M.

Polish Journal of Chemical Technology

2005

Vol. 7, nr 3

81-86

The investigation on incorporating the nitrogen group into titanium dioxide (Degussa P25) in order to obtain a visible-light active TiO2-xNx photocatalyst was performed. Titanium dioxide was modified by a heat treatment at different temperatures (450, 500 and 550°C) in ammonia atmosphere for 3, 6, 8 or 10 hours, respectively. The presence of the nitrogen groups on the catalyst surface was determined by the Fourier Transform Infrared Spectroscopy (FT-IR). The amount of the nitrogen built in TiO2 was determined on the basis of the thermogravimetric analysis (TG/DTA). It was found that the modification of TiO2 with ammonia resulted in a shift of the absorption spectrum of TiO2 towards solar spectrum wavelength (lmax = 479 nm; EG = 2.59 eV). The sample of the highest photoactivity contained ca. 2% of nitrogen. The modification of titanium dioxide with nitrogen increases the range of practical applications of TiO2 in water treatment processes due to the enhancement of its activity under both UV and visible light. This gives the possibility to utilize the solar light.