Reconciling the activity-selectivity trade-off in acrylonitrile oxidation via synergistic hydrolysis-oxidation over hierarchical Fe/Cu-ZSM-5.

The inherent trade-off between catalytic activity and N2 selectivity, coupled with the intricacy of reaction pathways, remains a formidable hurdle in the selective catalytic oxidation (SCO) of nitrogen-containing volatile organic compounds (NVOCs). Herein, a hierarchical Fe/Cu-ZSM-5 catalyst was synthesized via a hydrothermal-induced self-assembly strategy to reconcile this conflict in acrylonitrile oxidation. The optimized 30Fe/Cu-Z catalyst exhibits exceptional performance, achieving ca. 99% conversion at 325 °C while maintaining >99% N2 selectivity over a wide operating temperature window (ΔT = 150 °C), and showing fully reversible catalytic performance under humid conditions. Comprehensive characterization reveals that the introduction of Fe species optimizes the balance between surface reactive oxygen species and acid sites. Mechanistically, a synergistic hydrolysis-oxidation pathway was proposed wherein surface dispersed α-Fe2O3 species act as hydrolysis centers to efficiently activate CN bonds, while Cu2+ species and strong acid sites within ZSM-5 function as internal selective catalytic reduction (i-SCR) centers. This spatial configuration ensures the rapid capture and selective conversion of hydrolysis-derived NH3 intermediates into N2, effectively mitigating the formation of hazardous nitrogen oxides (NOx) typically associated with conventional impregnation methods. This study provides a promising strategy for designing multi-site catalysts for the deep purification of complex NVOCs.