Catalytic reduction of nitrogen dioxide by carbon monoxide

Abstract

Rate data for the catalytic partial reduction of nitrogen dioxide with carbon monoxide were obtained using a flow reactor operated differentially at atmospheric pressure and at temperatures of 180–240°C. A barium-promoted copper chromite catalyst was used. Nitrogen dioxide and carbon monoxide partial pressures were varied from 0.02 to 0.12 atm using helium as a diluent to bring the total gas flow to 4000 ml/min or a space velocity of 50,000 hr −1. Under these conditions, the only important reaction products were nitrogen monoxide and carbon dioxide. Changes in reactant concentrations had significant effects on the chemical nature of the catalyst. Nitrogen dioxide appeared to be strongly adsorbed on the catalyst surface. Increasing NO 2 partial pressure caused the reaction rate to decrease. The rate increased approximately linearly with increasing partial pressure of CO, suggesting that the adsorption of CO was the controlling step in the reaction.