Oxide–Oxide Interactions Dominating the Reaction Pathways in CO 2 ‐Assisted Oxidative Dehydrogenation of Ethane

Abstract

The CO 2 ‐assisted oxidative dehydrogenation of ethane (CO 2 ‐ODHE) has attracted increasing attention due to the dual benefits of ethylene production and CO 2 utilization. Among the CO 2 ‐ODHE catalysts, low‐cost Co‐based catalysts have received special interest recently. However, the complex chemical states of cobalt species lead to competing pathways in CO 2 ‐ODHE, casting a shadow on their application potential. Herein, we designed two identical‐composition Co 3 O 4 ‐ZrO 2 catalysts with different interfaces and found that the inverse‐structured Co 3 O 4 @ZrO 2 ‐IE synthesized via ion exchange achieved 83% ethylene selectivity; conversely, the traditional supported Co 3 O 4 /ZrO 2 ‐WI prepared by impregnation resulted in primarily CO formation. Comprehensive investigations based on in situ characterizations and theoretical calculations revealed that during the CO 2 ‐ODHE process, the weaker interfacial oxide–oxide interactions in Co 3 O 4 /ZrO 2 ‐WI made Co 3 O 4 readily reduced to metallic Co 0 , deeply scissoring C─H and C─C bonds, then reacting with O* derived from CO 2 dissociation, promoting the formation of C 2 H 5 O* and CH x * key intermediates leading to ethane dry reforming. Contrastingly, the enhanced oxide–oxide interactions in Co 3 O 4 @ZrO 2 ‐IE inhibited excessive reduction of Co 3 O 4 , forming stable interface‐confined Zr–O v –Co 2+ sites, favored C─H bond activation for the formation of C 2 H 5 *, while inhibiting C 2 H 5 O* and CH x *, thereby resulting in dehydrogenation to ethylene. This work highlights modulating oxide–oxide interactions as a new strategy for fabricating advanced catalysts.