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 (γ-Al₂O₃ and ZSM-5) on the atomic catalytic activity of supported copper and cobalt cations in the reactions of selective reduction of NO by propane and complete oxidation of propane by molecular oxygen in the presence of nitrogen oxide was considered. It was concluded that the acid sites of a support are not involved directly in the activation of nitrogen oxide or the hydrocarbon in the systems containing transition metal cations. The support acidity exerts an indirect effect on the activity and selectivity of these systems and determine to a considerable extent the proportion of clustered and isolated cations. The analysis of experimental data showed that, in a moderately high temperature region (700 K) for dry reaction mixtures, the isolated cations are mainly responsible for the route of propane oxidation by molecular oxygen, whereas the selective reduction of oxides occur on the clustered sites.