Proximity-Dependent Oxide–Support Interactions in Cobalt/Ceria-Based Catalysts for Propane Dehydrogenation

The CoOx-based catalyst has attracted extensive research interest for propane dehydrogenation. However, enhancing its performance has been challenged by uncertainties surrounding the valence states of cobalt. This paper describes the pivotal role of proximity-dependent Co2+ in cobalt/ceria-based catalysts for nonoxidative propane dehydrogenation. By combining transmission electron microscopy and in situ spectroscopies, we discovered that Co2+, stabilized by the cooperative CoOx–CeOx interface, rather than metallic Co0, is responsible for activating the C–H bonds of propane. For the 1Co/20CeAl catalyst, where CoOx and CeOx are in intimate contact at the nanoscale, the highest Co2+ content was achieved, leading to the highest space–time yield (STY) of propylene with a high selectivity of 86%. Kinetic studies indicate that the proximity-dependent oxide–support interaction mediates the Co0/Co2+ ratios, resulting in a shift in the rate-determining step from the first C–H bond activation in 1Co/Al to the second C–H bond activation in 1Co/20CeAl. This study emphasizes the utilization of oxide-support interactions to optimize catalytic performance.