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

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. [Display omitted] •BaMnO3 introduced into and confined by the mesopores of hierarchical SSZ-13 form small-scale nanocrystals of 5–10 nm.•The introduction of BaMnO3 improves the acid capacity and NO adsorption capacity.•Abundant oxygen vacancies and excellent lattice oxygen mobility are the incentives for the strong oxidation ability.•The synergistic effect of BaMnO3 and Cu optimizes the chemical environment of Mn and enhances the reducing ability.•The active bidentate nitrate species and unique ads-NO2 species is the crucial reason for the excellent activity.