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.

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Prins condensation of methyl tert-butyl ether (MTBE) with formaldehyde (FA) is an important route for isoprene synthesis. Traditionally, the production capacity of isoprene in a liquid-phase batch reactor is significantly limited due to the high ratio of MTBE/FA and the addition of an excessive amount of solvent. In this study, we evaluated different acid catalysts aiming at enhancing the selectivity and recyclability of catalysts under the condition of stoichiometric MTBE/FA in a concentrated solution. A Brønsted sulfonic ionic liquid ([HSO 3bmin] PTS) showed remarkable performance. The study of the reaction network confirmed that 4,4-dimethyl-1,3-dioxane (DMD) was the key reaction intermediate for isoprene synthesis. Sufficient acid strength of the ionic liquid catalysts was necessary for the conversion of intermediates to isoprene. The influence of reaction conditions including reaction time, reaction temperature, solvent, SO 3 H-functionalized ionic liquid (SFIL) concentration, and the amount of MTBE and formaldehyde was investigated in detail to maximize the yield of isoprene. Under the optimal conditions, the capacity of isoprene production reached 55.0 g/L, 1 order higher than that in previous studies. The [HSO 3 -bmin] PTS ionic liquid exhibited excellent recyclability and maintained its activity and selectivity after being reused seven times.