Subsurface nickel boosts the low-temperature performance of a boron oxide overlayer in propane oxidative dehydrogenation

Oxidative dehydrogenation of propane is a promising technology for the preparation of propene. Boron-based nonmetal catalysts exhibit remarkable selectivity toward propene and limit the generation of COx byproducts due to unique radical-mediated C-H activation. However, due to the high barrier of O-H bond cleavage in the presence of O2, the radical initialization of the B-based materials requires a high temperature to proceed, which decreases the thermodynamic advantages of the oxidative dehydrogenation reaction. Here, we report that the boron oxide overlayer formed in situ over metallic Ni nanoparticles exhibits extraordinarily low-temperature activity and selectivity for the ODHP reaction. With the assistance of subsurface Ni, the surface specific activity of the BOx overlayer reaches 93 times higher than that of bare boron nitride. A mechanistic study reveals that the strong affinity of the subsurface Ni to the oxygen atoms reduces the barrier of radical initiation and thereby balances the rates of the BO-H cleavage and the regeneration of boron hydroxyl groups, accounting for the excellent low-temperature performance of Ni@BOx/BN catalysts.