Unveiling Thickness-Dependent Interfacial Synergy in Inverse M@BO x Catalysts for Highly Efficient Oxidative Dehydrogenation of Propane

The BO x overlayer, promoted by a subsurface metal promoter in the M@BO x core–shell configuration, exhibits high activity and selectivity in the low-temperature oxidative dehydrogenation of propane (ODHP). However, the inverse interfacial interactions between metal and the BO x overlayer remain incompletely understood. In this study, we present a bottom-up synthetic strategy for fabricating Ru@BO x inverse catalysts with tunable boron oxide overlayer thickness by varying CO 2 concentrations during the oxidation etching process. The results demonstrate a pronounced BO x shell thickness-dependence of the low-temperature ODHP performance of Ru@BO x /BN catalysts. The promotional effect of subsurface metal lies in enhancing the density of hydroxylated BO x active sites and modulating the electronic structure of the BO x overlayer via electronic interfacial interactions. The promotion is confined to the bottom few layers of BO x on Ru NPs and decreases rapidly with increasing shell thickness.