Mechanism of N2 formation over the FeO-MnO2/SiO2 (100) surface in low-temperature NH3-SCR process: Electronic analysis of reaction pathways and key intermediates

Density Functional Theory (DFT) was used to study the process and details of N2 formation on the FeO-MnO2/SiO2 (100) surface during selective catalytic reduction of NH3 (NH3-SCR). The Fe and Mn sites on the surface of the FeO-MnO2/SiO2 (100) play important roles in denitrification. NH3 forms stable chemical adsorption on its surface, especially with stronger adsorption capacity on the Fe sites than on the Mn sites. Furthermore, Fe sites demonstrate better performance in NH3 dehydrogenation reactions in comparison to Mn sites, but the key intermediate NH2NO tends to form on the Mn sites. NH2NO may generate N2 through a dehydrogenation reaction at the Fe sites on the catalyst surface, while it is more inclined to decompose and generate N2 through internal migration on the Mn sites. These results help to deepen the understanding of the micro-mechanism of catalysts in N2 generation, laying a theoretical foundation for improving the denitrification performance and N2 selectivity of catalysts. [Display omitted]