Ag and Cu partitioned on SSZ-13/γ-Al2O3 composites: Synergistic enhancement of NH3-SCO.

SSZ-13 and γ-Al2O3 were composited by ball milling, and the Ag/Cu-AlS3 catalyst was successfully prepared, exhibiting excellent catalytic performance and high economic efficiency. Introducing γ-Al2O3 effectively modulated the reaction mechanism of the Ag/Cu-SSZ-13 catalyst. More importantly, a significant synergistic effect between Ag and Cu was observed across different temperature regions. At low temperatures (<200 °C), surface Ag species primarily activated NH3 to generate NOx, thereby lowering the reaction energy barrier, while Cu species within the pores served as the primary active centers, dominating the internal-selective catalytic reduction (i-SCR) mechanism and endowing the catalyst with excellent low-temperature activity. When the reaction temperature exceeded 200 °C, the reaction mechanism switched to the N2- mechanism, which was dominated by the Ag/Al2O3 component. Meanwhile, Cu species further lowered the reaction energy barrier through synergy, ensuring a smooth transition of the N2- mechanism after the i-SCR process and achieving efficient NH3 elimination over a wide temperature range.