Mesoporous zeolite ZSM-5 confined Cu nanoclusters for efficient selective catalytic reduction of NOx by NH3

Cu-based catalysts have been widely used in ammonia-selective catalytic reduction (NH₃-SCR) of NO_x for their excellent low temperature denitration performance. However, the aggregation of Cu species has been a troubling problem in catalyst design. Herein, spherical zeolite ZSM-5 confined Cu nanoclusters Cu@ZSM-5 has been successfully constructed via in-situ self-assembly process. It exhibits high specific surface area (373 m²g⁻¹), higher concentration of Cu⁺, rich oxygen vacancies and more acid sites compared with Cu/ZSM-5. The results indicate that strong acid sites of carrier could improve high-temperature catalytic activity, and Cu species as active sites could significantly improve both the low-temperature and high-temperature catalytic reduction activity of NO_x, especially, its performance maintained unchanged after coating on honeycomb ceramics. Thanks to strong surface acidity sites and the confinement effect, the Cu@ZSM-5 exhibited super activity, high N₂ selectivity, wide operating temperature window and strong water resistance.