TiO2-supported Noble Metal Catalysts for the NO–CO and NO–CO–H2O–H2–O2 Reactions

TiO2-supported noble metal catalysts, such as Pt–, Pd–, and Rh–TiO2, are much more active for the NO–CO reaction in the presence or absence of H2O, H2, and O2 than the corresponding Al2O3– or other supported catalysts. They are effective even in an oxidative gas composition range for the NO–CO–(H2O)–H2–O2 reaction, producing no NH3 in the NO–CO–H2O reaction. Comparison of the catalytic activity and properties of Pt–TiO2 with those of other supported catalysts suggests that the higher activity of the TiO2-supported catalysts could be attributed to their ability to activate NO molecules by the dissociative adsorption at lower temperatures.