Nitrogen-15 Tracer Investigation of the Mechanism of the Reaction of NO with NH3 on Vanadium Oxide Catalysts

Article abstract of DOI:10.1021/j100212a027

15N tracers have been applied in a pulse reactor to investigate the mechanism of the reaction of NO with NH3 on V2O5, V2O5/TiO2, V2O5/Al2O3, and V2O4 catalysts.As for the N^-O-NH3 reaction (N^- represents the labeled nitrogen atom) on the V2O5, V2O5/TiO2, and V2O5/Al2O3 catalysts at temperatures below 300 deg C, NN^- was selectively produced while NN^-O, N^-N^-, N^-N^-O, NO, NN, and NNO were not.These data strongly support the previously proposed mechanism for the NO-NH3 reaction on V2O5 and assure its application to supported V2O5 catalysts.As for the N^-O-NH3 reaction on V2O5 at temperatures above 300 deg C, NN^-O, NN, NO, and NNO were produced in addition to NN^-.The conversion of N^-O went through a maximum at 400 deg C, which is similar to the behavior found for the conversion of NO in the NO-NH3 reaction in the presence of O2 under the dilute gas condition.The N^-O-NH3 reaction on the V2O4 catalyst produced N^-N^- and N^-N^-O in addition to NN^- and NN^-O, and the selectivities to NN^-, NN^-O, N^-N^-, and N^-N^-O were determined as functions of reaction temperature and catalyst weight.The mechanisms of the NO-NH3 reaction on V2O5 catalyst at high temperatures and that of V2O4 catalyst are proposed.