The mechanism of the reaction of nitrogen oxide with ammonia over Cr 2O 3Al 2O 3 and Cr 2O 3 catalysts : II. Isotope labeling studies

Abstract

The reaction of NO with 15NH 3 was studied over 9.3% Cr 2O 3Al 2O 3 and Cr 2O 3 as catalyst; relevant properties characterizing these oxides are described in Part I (preceding paper). The main isotope species in the products, nitrogen and nitrous oxide, were 15NN and NNO when the reaction proceeds in a stationary state. A noncatalytic reaction of NO with prereduced surface to give NN was also significant, especially in the beginning. When the catalyst was preoxidized, the reaction was greatly enhanced and a large amount of 15NNO was found. It is concluded that the reaction takes place on surface oxygens.