Enhancement of N2O decomposition performance by N2O pretreatment over Ce-Co-O catalyst

Abstract

A series of Ce-Co-O binary oxides catalysts were synthesized by co-precipitation methods and tested for catalytic decomposition of N2O. The catalyst with 10 mol% of Ce showed superior activity. Significant enhancement of decomposition performance over N2O-pretreated Ce-Co-O catalysts was observed. The fresh, N2O-pretreated Co3O4 and Ce-Co-O catalysts were characterized by XRD, Raman, XPS, H2-TPR, TPD studies. It was found the deposited oxygen species (O∗), which generated from the dissociation of N2O, was responsible for the enhancement by N2O pretreatment. Due to the excellent oxygen storage capacity of CeO2, deposited O∗ could transfer from Co3O4 crystallites to CeO2 crystallites during the regeneration process of active sites. Pretreatment of N2O at high temperature resulted in much abundant deposited O∗ on the surface. After cooling temperature, the accumulation of massive O∗ would arouse another surface-to-N2O electron transfer route (from O∗ to N2O), leading to the cleavage of the NO bond. Meanwhile, the results revealed that the existence of electron transfer from catalysts to N2O was possible.