Metal-free silicon boride catalyst for oxidative dehydrogenation of light alkanes to olefins with high selectivity and stability

Abstract

Due to the free coking and no equilibrium limitation in alkanes conversion, the oxidative dehydrogenation of light alkanes to olefins offers an attractive route, but encounters the difficulty in selectivity control for olefins because of the over-oxidation reactions that produce a substantial amount of CO2. Here we report silicon boride exhibiting good oxidation resistance property at high temperature, as a metal-free catalyst efficiently catalyzed dehydrogenation of light alkanes to olefins with a high selectivity at a given reaction conditions. The stability was evidenced by the operation of a 100-h test with steady conversion and product selectivity. When the conversion of ethane, propane and isobutane reached 18.8%, 19.1% and 6.0%, the selectivity of olefins were up to 98.0%, 94.4% and 96.4%, respectively. This work experimentally supports that the catalytic origin of the boron species from the metal-free catalyst initiate the oxidative dehydrogenation of light alkanes.