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

Abstract

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 Ce³⁺ and Ce⁴⁺ in CeO₂ facilitates the formation of cobalt ions in the high valence state and the Co–N_x 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.