NO-CO, NO-H2, NO-C3H6, and NO-NH3 reactions have been investigated on a number of transition metal oxide catalysts by pulse reaction technique. The catalysts have been divided into two groups with respect to their behaviors to the above reactions. Namely, Fe2O3, Cr2O3, CuO, Co3O4, NiO, MnO2, and ZnO catalysts (group A catalysts) are active for all reactions, whereas V2O6, MoO3, WO3, and SnO2 catalysts (group B catalysis) are active only for NO-NH3 and NO-C3H8 reactions but inactive for NO-CO and NO-H2 reactions. These results showed that mechanisms of NO-NH3 and NO-C3H6 reactions may be different from that of NO-H2 (or NO-CO) reaction. The activity of group A catalysts for NO-NH3 reaction is proportional to that for NO-H2 (or NO-CO) reaction, which suggested that a close relationship between the mechanisms of NO-NH3 and NO-H2 (or NO-CO) reactions may exist on group A catalysts. The selectivity of N2 in NO-NH3 reaction on group A catalyst is lower than that on group B catalysts. The differences in behavior between group A and B catalysts were also found in the kinetics of NO-NH3 reaction. Namely, reaction rate of NO-NHa reaction is proportional to PNH3-0.03 PNO-0.90 on V2O5 catalyst (group B catalyst) and to Pj^PNH30.32 PNO0.5 g Fe2O3 catalyst (group A catalyst). It has been inferred that the rate of NO adsorption and the reduction of adsorbed NO by adsorbed hydrogen are slower on V2O5 catalyst than on Fe2O3 catalyst.
ASJC Scopus subject areas
- Chemical Engineering(all)