Effects of Ni/Ce doping on the anti-sulfur and anti-water properties of β-MnO2 (1 1 0) surface: A density functional theory study

Abstract

Mn-based catalysts have excellent deNOx performance, but they suffer from the toxic effects of SO2 and H2O easily. Ni and Ce doping can enhance SO2 and H2O resistance of Mn-based catalysts, while the microscopic mechanism of modification remains unclear and needs further investigation. In this study, the effects of Ni and Ce doping on SO2 and H2O resistance over the β-MnO2 (1 1 0) surface was explored by a density functional theory. Results indicate that Ni and Ce doping can limit the adsorption of SO2 and H2O at the main sites, especially Ce doping. Although Ce cannot prevent SO2 from occupying the Ce-top site, it promotes the production of Brønsted acid sites on the surface, which is conducive to SCR deNOx reaction. The presence of Ce has a greater inhibitory effect on SO2 oxidation than Ni, which can inhibit the formation of (NH4)2SO4 and NH4HSO4. In addition, Ce can significantly promote the dissociation of *H2O and thus re-expose the Lewis active sites to the NH3-SCR process. These results offer insights into the mechanism of modification at the molecular level not available experimentally and provide theoretical guidance for the development of Mn-based catalysts with improved SO2 and H2O resistance.