The influence of support on catalytic properties of copper- and cobalt-containing catalysts for selective reduction of nitrogen oxides with propane in excess oxygen

The influence of acid properties of supports (gamma-Al2O3 and ZSM-5) on the atomic catalytic activity of supported copper and cobalt cations in the re actions of selective reduction of NO by propane and complete oxidation of p ropane by molecular oxygen in the presence of nitrogen oxide was considered . It was concluded that the acid sites of a support are not involved direct ly in the activation of nitrogen oxide or the hydrocarbon in the systems co ntaining transition metal cations. The support acidity exerts an indirect e ffect on the activity and selectivity of these systems and determine to a c onsiderable extent the proportion of clustered and isolated cations. The an alysis of experimental data showed that, in a moderately high temperature r egion (700 K) for dry reaction mixtures, the isolated cations are mainly re sponsible for the route of propane oxidation by molecular oxygen, whereas t he selective reduction of oxides occur on the clustered sites.