Facile synthesis of Schistose-like Co-Mn oxides for low-temperature catalytic oxidation of NO with enhanced SO2/H2O tolerance

Abstract

The schistose-like Mn-Co oxides were synthesized by thermal decomposition of inorganic salts as catalyst for NO oxidation. The morphological and surface structural properties can be efficiently regulated by controlling the ratio of Co/Mn. Schistose-layered structure with plentiful nanopores not only facilitates the exposure of active sites but also improves the diffusion and adsorption of NO. Abundant active oxygen species and highly content of Mn4+ formed on the surface of Co1Mn4 play a vital role in the catalytic oxidation of NO. Thus, Co1Mn4 catalyst achieves the highest conversion rate of 54.4 % at 120 °C and 91.3 % at 240 °C. Moreover, satisfactory long-time stability as well as outstanding tolerance to SO2 and H2O could be obtained for Co1Mn4 catalyst. Distinct distinctions on the variation of nitrate/nitrite species over Mn and Co1Mn4 are discovered by in-situ DRIFTS, which provided basis for elucidating the reaction mechanism. This work broadens the horizons for the design of bimetallic catalysts for low-temperature NO oxidation.