A Novel Low-Temperature Fe-Fe Double-Atom Catalyst for a “fast SCR” Reaction

Theoretically designing a catalyst with high catalytic activity for ammonia selective catalytic reduction (NH3- SCR) reaction at low temperature to guide the subsequent experimental synthesis, which is of great significance for controlling the emission of NOx. Herein, we examine for the first time Fe2-N6 catalysts as candidates for this application at a theoretical level. The adsorption behavior of various gases, catalytic mechanism of the NH3-SCR reaction, and turnover frequency were analyzed using density functional theory calculations (DFT) and micro -kinetic modeling. We found that a "fast SCR" reaction is the dominant path of the NH3-SCR reaction. The energy barrier for the rate-determining step (HONO formation) is 1.00 eV, much lower than that of other SCR catalysts. In addition, the Fe2-N6 catalyst exhibits outstanding low-temperature activities in the temperature window from 300 to 500 K.