Study the low-temperature SCR property of M-doped (M=Ni, Cr, Co, Se, Sn) MnO2(100) through density functional theory (DFT): Improvement of sulfur poisoning resistance

Abstract

Modification of manganese-based selective catalytic reduction (SCR) catalyst by five kinds of the element was studied to improve its SO2 resistance. In this paper, density functional theory (DFT) calculation was used to analyze the effects of doped atom on electronic dispersion and crystal structure of MnO2(100). Our result demonstrated that the doping of Ni, Cr, and Co could increase the strength of Lewis acid sites for the manganese-based catalyst, while Se and Sn decrease that. On the other hand, the manganese-based catalyst modified by Se and Sn present better resistance to sulfur poisoning. By comparing the dissociation energy barrier of NH3 over different element doped catalyst and analyzing the partial density of state (PDOS) for SO2 adsorbed on the catalyst, we found that Cr could be as a potential dopant modifying the manganese catalyst, because of it could convert sulfur to Brønsted acid sites which catalyze NH3-SCR through followed the LH-mechanism.