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 H-2-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 N-2 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 CxHyOz species (enolic species and acetate) on the surface, followed by the formation of hydrocarbonate or carbonate as intermediates to directly generate N-2, CO2 and H2O.