Effect of chemical and physical properties of titanium oxide support surface during nitrogen monoxide reduction by carbon monoxide in presence water over titanium oxide supported platinum catalyst

The selective conversion of NO_x to NH₃ through the NO – CO - H₂O reaction over Pt/TiO₂ catalysts was investigated to develop a method for utilizing reactive nitrogen species emitted from combustion processes as raw materials for the synthesis of useful compounds. High NH₃ selectivity was achieved for high-specific-surface-area catalysts. Catalytic activity tests showed that the activities of catalysts depended on the crystal structure of the support. Comparing CO conversion between NO – CO - H₂O reaction and CO - H₂O reaction, which could play a role of H-supply reaction, Pt/TiO₃ demonstrated higher CO conversion for the NO – CO - H₃O reaction than that for CO - H₂O reaction except for high-surface-area anatase TiO₂-supported catalyst around 200°C. Temperature-programmed desorption of CO₂ revealed that the CO₃ formed during the NO – CO - H₂O reaction had no effect on the difference in activity. Carbonaceous surface species and NH_x species were observed on the surface of Pt/TiO₂ catalyst during NO – CO - H₂O reaction by diffused reflectance infrared Fourier transform spectroscopy. The difference in formate formation on anatase-TiO₂ supported Pt catalyst was confirmed compared to rutile-TiO₂ supported Pt catalyst.