Mesoporous–optimized BaMnO3 perovskite small-scale nanocrystals in SSZ-13 to enhance activity for the selective catalytic reduction reaction of NO

Abstract

As one of the cores of ammonia-selective catalytic reduction technology (NH3-SCR), conventional microporous Cu-SSZ-13 has developed hierarchical pores in recent years. The reasonable use of newly mesoporous channels to improve catalytic activity has become a new challenge. We designed novel hierarchical Cu-SSZ-13 catalyst supported with BaMnO3 perovskite, which exhibited excellent low-temperature SCR activity. A series of characterizations illustrated that BaMnO3 was introduced into mesopores located in hierarchical Cu-SSZ-13 and form small-scale nanocrystals of 5–10 nm, which significantly improves the ability to oxidize NO to NO2. In addition, the synergistic effect caused by introduced BaMnO3 and Cu species makes BaMnO3-Cu-SSZ-13 have higher Mn4+ proportion and stronger redox ability. In situ DRIFTS experiments revealed that the introduced BaMnO3 enhanced the reactivity of ammonia and NOx species. Different from the monodentate nitrate observed on Cu-SSZ-13, the reaction intermediate bidentate nitrate and ads-NO2 appeared on BaMnO3-Cu-SSZ-13 in the reaction process, which is also a crucial reason for the higher low-temperature activity.