Modulation of acidic and redox properties of Mn-based catalysts by Co doping: Application to the synergistic removal of NOx and chlorinated organics

Abstract

The synergistic catalytic removal of nitrogen oxides (NOx) and chlorinated volatile organic compounds (CVOCs) mainly depends on the redox properties (RP) and surface acidity (SA) of the catalyst. Striking the right balance between these factors is the key to ensuring both the high efficacy of synergistic removal and the exceptional selectivity of N2 and CO2. This study aims to regulate the RP and SA of catalysts by adjusting the Co/Mn ratio, with the goal of exploring their impact on NOx/chlorobenzene (CB) synergistic removal performance. The results showed that after Co doping, some Co entered the Mn cells to form MnCo2O4 which together with the residual Co and Mn regulated the PR and SA of the catalyst. The RP of the catalysts increased with the increase of Co doping, and the SA showed a tendency to increase and then decrease. When the Co doping amount was 40 %, the RP and SA reached a good balance, which made the Mn6Co4Ox catalyst show outstanding catalytic activity. The NOx conversion was higher than 90 % in the temperature range of 104–275 °C, and 90 % CB conversion was achieved at 181 °C. These observations are anticipated to serve as a valuable reference for practical applications of NOx/CB synergistic removal.