Computer simulation method has been applied to the analysis of the kinetics of NO-NH3 reaction on metal oxide catalysts. Rate constants of elementary steps in the NO-NH3 reaction have been determined by the least squares method for V2O4 and Fe2O3 catalysts to elucidate the differences in their catalytic properties. The results showed that the adsorption of NH3 is faster on V.O, than on Fe2O3, whereas the adsorption of NO and the reaction of adsorbed NO with adsorbed hydrogen are faster on FeA than on V2O4. The effects of surface oxygen on the rates of NO-NH3 and NO-H3 reactions have been studied on the vanadium oxide catalyst It has been found that the rate of NO-NH, reaction is markedly enhanced by surface oxygen (V=0 species) whereas the rate of NO-H3 reaction is significantly decreased. The promotive effect of the surface oxygen in the former reaction has been shown to arise from the following two actions of surface oxygen; the removal of adsorbed hydrogen dissociated from NH3 and the acceleration of the adsorption of NO. On Fe2O3. MnO3 Cr2O3, ZnO and NiO catalysts. (group A catalysts), the activity for NO-NH3 reaction has been found to be parallel to that for NO-H2 reaction. The correlation has been explained in terms of the difference in the rates of the reactions of adsorbed NO with adsorbed hydrogen derived from NH3 or H,; the larger the rate constants of the steps, the faster the rates of both NO-H3 and NO-NH3 reactions. Further, guides to the improvement of V2O3 and F2sO, catalysts for NO-NHe reaction were given on the basis of the rate constants obtained.
ASJC Scopus subject areas
- Chemical Engineering(all)