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

Abstract The BOx overlayer, promoted by a subsurface metal promoter in the M@BOx 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 BOx overlayer remain incompletely understood. In this study, we present a bottom-up synthetic strategy for fabricating Ru@BOx inverse catalysts with tunable boron oxide overlayer thickness by varying CO2 concentrations during the oxidation etching process. The results demonstrate a pronounced BOx shell thickness-dependence of the low-temperature ODHP performance of Ru@BOx/BN catalysts. The promotional effect of subsurface metal lies in enhancing the density of hydroxylated BOx active sites and modulating the electronic structure of the BOx overlayer via electronic interfacial interactions. The promotion is confined to the bottom few layers of BOx on Ru NPs and decreases rapidly with increasing shell thickness.