Efficient simultaneous removal of NOx and CO at low temperatures over integrated Mn2Co1Ox/iron mesh monolithic catalyst via NH3-SCR coupling with CO oxidation reactions

Abstract

NOx and CO are two main pollutants in the coke oven flue gas emissions, and their treatment faces huge challenges. Under oxygen-enriched conditions, CO is rapidly oxidized to CO2 prior to proceed CO-SCR reaction, therefore, NH3-SCR technology incorporated with CO oxidation reaction is a promising approach to remove NOx and CO simultaneously. Considering the practical application, so far, there is no efficient monolithic catalyst capable of removing NOx and CO pollutants simultaneously at low temperatures (160–200 °C). In this paper, Mn2Co1Ox/iron mesh (IM) monolithic catalysts were developed using a hydrothermal method. By tuning the redox properties, surface acidity, and oxygen vacancies, the optimized catalyst exhibits an outstanding catalytic performance (99.7% NOx conversion and 98.2% CO conversion at 160 °C) and excellent water and SO2 resistance. The synergistic effect and interaction mechanism between NH3-SCR and CO oxidation are systematically revealed by correlation characterization and DFT calculations. It was found that Mn2Co1Ox/IM has advantages in adsorbing NH3 and CO at Mn and Co sites, respectively, which weaken the inhibition of CO oxidation by NH3. Besides, a strong interaction and charge transfer take place between Fe substrate and the active component which affect the surface-active sites, further improving the activity of Mn2Co1Ox/IM. We believe that this synthesis of efficient integrated catalysts has potential application prospects in coke oven flue gas treatment.