Photocatalytic Degradation of NOx Over Platinum and Nitrogen Codoped Titanium Dioxide Under Visible Light Irradiation
In order to utilize visible light and enhance the catalytic efficiency in photocatalytic conversion of NOx, nitrogen and platinum atoms were doped in commercially available photocatalytic TiO2 powders by impregnating and photodeposition methods, respectively. X-ray diffraction (XRD) showed that the crystal structures of TiO2 were not changed after the doping process. Analysis by X-ray photoelectron spectroscopy (XPS) indicated that N atoms were incorporated in the bulk phase of TiO2 as N-Ti-O linkages and Pt atoms were at the surface. A significant shift of the absorption edge to lower energy and higher absorption in the visible light region were observed. This Pt,N-codoped TiO2 powder exhibited excellent photocatalytic activity and fairly stable chemical property for the degradation of NOx under visible light irradiation. The sample mixed with 20 wt.% ammonium carbonate and doped with 0.5 at.% platinum atoms showed the best photocatalytic activity and its activity can be restored by rinsing with water after long-term operation.