Synergistic removal of NOx and CB by Co-MnOx catalysts in a low-temperature window

[Display omitted] •The Co-modified MnOx catalyst formed MnCo2O4 solid solution.•Co doping added additional Lewis acid sites and promoted the conversion of Mn2+ to Mn3+ and Mn4+.•Co addition effectively reduced the energy barriers for N-H cleavage and oxygen vacancy formation. The simultaneous removal of NOx and CVOCs in a deNOx unit has gained significant attention in recent years. However, efficient co-removal of NOx and CVOCs is still a challenge due to the low tail gas emission temperatures in the non-electric industry. To address this, m-MnOx (m = Sn or Co) catalysts were prepared based on the Mn-based catalyst to investigate their catalytic performance in removing NOx and CB. The results demonstrated that the Co-MnOx catalyst exhibited the best catalytic activity, achieving over 90 % NOx conversion within the temperature window of 105–275 °C, while CB conversion rates surpassed 90 % above 180 °C. The characterization results revealed that Co doping formed MnCo2O4 adding additional Lewis acid sites and promoted the conversion of Mn2+ to Mn3+ and Mn4+, thereby improving the redox ability and surface acidity of the Co-MnOx catalyst. DFT simulations revealed that Co addition improved the adsorption of NH3 and CB on the Co-MnOx catalyst and effectively reduced the energy barriers for N-H cleavage and oxygen vacancy formation. This work is hoped to provide an important reference for the further design and optimization of efficient low-temperature NOx/CB synergistic removal catalysts.