Mobility of Cu Ions in Cu-SSZ-13 Determines the Reactivity of Selective Catalytic Reduction of NO<sub><i>x</i></sub> with NH<sub>3</sub>
Hwangho Lee, Inhak Song, Se Won Jeon, Do Heui Kim
Abstract
Selective catalytic reduction of NOx with NH3 (NH3–SCR) in Cu-SSZ-13 has been proposed to have a unique homogeneous-like mechanism governed by the spatial proximity of mobile Cu ions. Among factors that determine the proximity, the effect of ion density on the SCR reaction is well established; however, it has not been verified how the different mobility of the Cu ion influences the SCR reaction. Herein, we try to reveal the mobility-dependent SCR reaction by controlling the Cu species with different ion mobilities in Cu-SSZ-13. Since the reaction kinetics is governed by the diffusion of Cu ions, the Cu ion mobility determines the reactivity of the Cu-SSZ-13. In terms of this correlation, enhanced ion mobility leads to improved NH3–SCR activity. These findings help understand the behavior of Cu ions in Cu-SSZ-13 under a catalytic reaction and provide insights to design rational catalysts by tuning the ion mobility.