Preparation of a visible light-responding photocatalyst via nitrogen doping to titanium(IV) oxide modified with a silane coupling reagent

A titanium(IV) oxide (TiO2) sample having a large surface area and showing a large visible light absorption was prepared by modification of commercial TiO2 With a silane coupling reagent and subsequent nitrogen doping with ammonia at 500 degrees C. The thus-prepared visible light-responding TiO2 sample was used photoinduced removal of gaseous nitrogen oxides (NO.) under irradiation from blue light-emitting diodes or white fluorescent lamp and exhibited higher level of NO, removal than nitrogen-doped unmodified TiO2. A remarkable improvement in NO, removal was achieved by removing silica species with sodium hydroxide solution presumably due to the large surface area for effective adsorption of NO, and storage of nitric acid, and sufficient efficiency for both visible light and UV light.