Photocatalytic oxidation of NOx by Pt-modified TiO2 under visible light irradiation

Photooxidation of NOx has been studied using titanium dioxide (Ishihara ST-01) treated with H2PtCl6. The experimental results indicate that Pt-modified TiO2 with different ligand structures can be synthesized according to the Pt treating procedure. TiO2 photocatalysts with certain Pt complexes produced significantly high photocatalytic activity under visible light irradiation without decreasing photoactivity under UV light irradiation. The visible-light-induced photocatalytic activity depended on the amount of Pt, but not greatly on the coordination number of Cl ions. It was suggested that the surface complex formation associated with Ti–O–Pt chemisorption dominated the visible light reactivity.