Improved Activity and H₂O Resistance of Cu-Modified MnO₂ Catalysts for NO Oxidation

Abstract

The catalytic oxidation of NO plays an important role in the process of DeNO x . In this study, a series of Cu–Mn–O x mixed metal oxides were prepared by a co-precipitation method. The NO oxidation performances indicated that the catalyst with a Cu:Mn molar ratio of 1:1 prepared at pH 6 (denoted CuMnpH6) exhibited the best activity. In the presence of H 2 O, the activity of the CuMnpH6 catalyst was improved obviously compared to those of the other samples. The basicity of α-MnO 2 was weakened after the addition of Cu. The basicity modification might inhibit the adsorption of H 2 O on surface oxygen atoms and likely promote the adsorption of NO over the CuMnpH6 catalyst. The redox properties were enhanced, and dual redox cycles existed during NO oxidation. The redox properties and surface basicity, which are related to the NO adsorption capacity, were correlated to the NO oxidation and resistance to H 2 O over Cu–Mn–O x catalysts.