Metal-organic framework-derived CeO₂-ZnO catalysts for C₃H₆-SCR of NO: an in situ DRIFTS study

Metal-organic framework (MOF)-based derivatives have attracted an increasing interest in various research fields. Here, we synthesized CeO₂-ZnO catalysts through the complete thermal decomposition of the Ce/MOF-5 precursor. The catalysts were characterized using XRD, FTIR, TG-DSC, SEM and H₂-TPR. It is found that the as-prepared CeO₂-ZnO is favorable for strengthening the interaction between Ce⁴⁺ and Zn²⁺. A significant improvement in the catalytic performance for C₃H₆-SCR of NO was found over the Ce-doped catalysts with the highest N₂ yield of 69.1% achieved over 5% CeO₂-ZnO. In situ DRIFTS and NO-TPD experiments demonstrated the formation of monodentate nitrates, bidentate nitrates, chelating nitrite, nitro compounds, nitrosyl and C H O species (enolic species and acetate) on the surface, followed by the formation of hydrocarbonate or carbonate as intermediates to directly generate N₂, CO₂ and H₂O.