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

The CoO x -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 Co 2+ in cobalt/ceria-based catalysts for nonoxidative propane dehydrogenation. By combining transmission electron microscopy and in situ spectroscopies, we discovered that Co 2+, stabilized by the cooperative CoO x –CeO x interface, rather than metallic Co 0, is responsible for activating the C–H bonds of propane. For the 1Co/20CeAl catalyst, where CoO x and CeO x are in intimate contact at the nanoscale, the highest Co 2+ 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 Co 0 /Co 2+ 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.