Trade-off between redox ability and reactive behaviors for acrylonitrile selective catalytic combustion over the Cu-Ce-based UZM-9 catalysts

[Display omitted] •CeO2 was feasible to enhance the reducibility of Cu species.•Cu-Ce-UZM-9 exhibited superior catalytic performance within wide temperature range.•Moderate redox ability of Cu species was achieved at the critical Ce content.•AN SCC reaction followed the hydrolysis mechanism over Cu-6.5-Ce-15%. In the study, the performance of acrylonitrile selective catalytic combustion over a series of Cu-Ce-based UZM-9 catalysts were evaluated, and the interaction between Ce (Ce3+ and CeO2) and Cu were systematically characterized by Ar adsorption-desorption, XRD, XPS, UV–vis, EPR and H2-TPR. The chemical state of Ce and Cu species were associated strongly with the loading amount of Ce, and there was a critical Ce content (about 15 wt%). For Cu-6.5-Ce-15 %, CeO2 could promote the shift of partial isolated Cu2+ to the outer surface of the crystals and weaken the interaction between Cu2+ and the zeolite. Then, the reducibility of Cu species could be significantly improved, which were the main active sites of the reaction. Comparing with Cu-6.5, the AN conversion activity and CO2 selectivity of Cu-6.5-Ce-15% were significantly improved and the excellent N2 selectivity was still maintained. Finally, in situ DRIFTS revealed that the reaction mainly followed hydrolysis mechanism over Cu-6.5-Ce-15%.