Poisoning mechanism of the coexistence K and SO2 on the deNOx of MnO2/TiO2 catalyst at low temperature

Manganese-based catalysts supported by TiO2 (MnO2/TiO2) show good deNOx performance at low temperature. However, the microscopic impact mechanism of poisonous substances such as K and SO2 on the deNOx of the MnO2/TiO2 catalyst is a grey area. In this work, the poisoning mechanism of K and SO2 coexistence on the deNOx of the MnO2/TiO2 catalyst was explored by using a density functional theory combined with experimental methods. SO2 has low adsorption performance on the MnO2/TiO2 (001) surface, while it can be oxidized to form SO3, and it will react with the catalyst to form sulfates. K poisoning makes NH3 and NO molecules more difficult to be adsorbed on the MnO2/TiO2 (001) surface. However, when SO2 is introduced on the catalyst surface with K poisoning, it can interact with K and change the charge transfer from K to the catalyst surface, alleviating the K poisoning of the catalyst. These results contribute to the understanding of the mechanism of K and SO2 co-poisoning on the deNOx of Mn-based catalysts at a microscopic level, and provide guidance for designing Mn-based catalysts with high anti-poisoning ability.