CO Oxidation over Anatase TiO2 Supported Au: Effect of Nitrogen Doping

Nitrogen doped yellowish anatase phase of titania support (TiO2-xNx) was prepared by hydrolysis of titanium (IV) butoxide with 15% NH4OH followed by filtration, drying and calcination at 450 degrees C for 3 h. For comparison, TiO2 was prepared by hydrolysing titanium (IV) butylate with distilled water. Deposition precipitation method was used for Au loading on TiO2-xNx and TiO2. These were characterised by XRD, Laser Raman spectroscopy, transmission electron microscopy, BET surface area analyser, and UV-visible spectrophotometry. UV-visible (diffused reflectance) spectrum of TiO2-xNx support shows a distinct absorption band around 450 nm wavelength indicating for N doping. Whereas, TiO2 does not show any absorption band in the visible region. The activity of gold loaded on these supports was tested for CO oxidation reaction. Effect of different pre-treatment conditions and effect of moisture on these catalysts were studied, and the results obtained were interpreted on the basis of nitrogen doping, optoelectronic properties, ability of oxygen uptake of the support and particle size of gold.