Study on the Mechanism of Co Oxidation and No Removal by Co-Scr Over Mfe2o4 (M=Co, Cu, Zn)

Abstract

In this article, we use density functional theory(DFT) to calculate the structures of Fe2O3 (001) and MFe2O4 (M=Co, Cu, Zn), then optimize the adsorption model of CO,NO and other molecules. In addition, the CO oxidation reaction and the selective catalytic reduction(SCR) reaction of CO+NO in CuFe2O4 and ZnFe2O4 were also explored. The results show that CO can be effectively adsorbed on these reactive substrates. After CO is adsorbed on the substrate, it will react with lattice oxygen to generate CO2 and oxygen vacancies to complete the CO oxidation reaction process. It can be judged from the reaction energy barrier that the performance of MFe2O4 is better than that of Fe2O3, and CuFe2O4 has better catalytic activity. Furthermore, due to the similar ionic radius, the reaction of CO+NO on CuFe2O4 and ZnFe2O4 is calculated. The energy barriers that need to be overcome on CuFe2O4 and ZnFe2O4 are 0.68eV and 0.73eV respectively，indicating the CO-SCR reaction is feasible on the catalyst surface. In conclusion, MFe2O4 (M=Co, Cu, Zn) catalyst can improve the catalytic activity of CO oxidation reaction and CO-SCR reaction, and CuFe2O4 has better selectivity and catalytic activity. This study also provides a new idea for catalytic co-removal of CO and NO.

Keywords: DFT, Spinel catalyst, CO oxidation, CO-SCR, Reaction mechanism