Influence of the synergistic effect between Co-N-C and ceria on the catalytic performance for selective oxidation of ethylbenzene.

A series of catalysts, i.e. metal oxides (MO) such as CeO2, Fe2O3 and Al2O3 supported Co-N-C (Co-N-C/MO) were prepared by heating supported cobalt porphyrin in a N2 atmosphere. Among the Co-N-C/MO catalysts, Co-N-C/CeO2 shows a remarkable catalytic performance for ethylbenzene oxidation with ethylbenzene conversion of 33.1% and selectivity to acetophenone of 74.8%. In addition, the interaction between Co-N-C and supports was tentatively characterized by techniques such as XRD, HRTEM, XPS etc. According to XPS, the presence of the redox cycle between Ce(3+) and Ce(4+) in CeO2 facilitates the formation of cobalt ions in the high valence state and the Co-Nx sites, which are typically responsible for the high catalytic activity. The high performance benefits from the synergistic effect between Co-N-C and CeO2 and the well-dispersed Co-based sites.