Selective oxidative dehydrogenation of propane to propene using boron nitride catalysts

Abstract

The exothermic oxidative dehydrogenation of propane reaction to generate propene has the potential to be a game-changing technology in the chemical industry. However, even after decades of research, selectivity to propene remains too low to be commercially attractive because of overoxidation of propene to thermodynamically favored CO Here, we report that hexagonal boron nitride and boron nitride nanotubes exhibit unique and hitherto unanticipated catalytic properties, resulting in great selectivity to olefins. As an example, at 14% propane conversion, we obtain selectivity of 79% propene and 12% ethene, another desired alkene. Based on catalytic experiments, spectroscopic insights, and ab initio modeling, we put forward a mechanistic hypothesis in which oxygen-terminated armchair boron nitride edges are proposed to be the catalytic active sites.

Construction of a Nanoporous Highly Crystalline Hexagonal Boron Nitride from an Amorphous Precursor for Catalytic Dehydrogenation

“…[32][33][34] But the realization of this future economy relies on the development of ah ighly efficient catalytic system for the reversibility and high selectivity of LOHC, [35] especially the N-ethylcarbazole (NEC) and dodecahydro-N-ethylcarbazole (12H-NEC) cycle systems. [34] Considering the highly efficient catalytic activity of h-BN in oxidative dehydrogenation of propane (ODHP) for olefin production, [11,12,37,38] we envisioned that the crystalline nanoporous h-BNNS obtained in this study could act as an efficient metal-free catalyst for the dehydrogenation of 12H-NEC.I ndeed, taking NEC-12H as am odel substrate (Figure 4), a74% yield of NEC was obtained using the as-prepared crystalline h-BNNS as the catalyst at al ow reaction temperature (120 8 8C). [34] Considering the highly efficient catalytic activity of h-BN in oxidative dehydrogenation of propane (ODHP) for olefin production, [11,12,37,38] we envisioned that the crystalline nanoporous h-BNNS obtained in this study could act as an efficient metal-free catalyst for the dehydrogenation of 12H-NEC.I ndeed, taking NEC-12H as am odel substrate (Figure 4), a74% yield of NEC was obtained using the as-prepared crystalline h-BNNS as the catalyst at al ow reaction temperature (120 8 8C).…”

“…[34] Considering the highly efficient catalytic activity of h-BN in oxidative dehydrogenation of propane (ODHP) for olefin production, [11,12,37,38] we envisioned that the crystalline nanoporous h-BNNS obtained in this study could act as an efficient metal-free catalyst for the dehydrogenation of 12H-NEC.I ndeed, taking NEC-12H as am odel substrate (Figure 4), a74% yield of NEC was obtained using the as-prepared crystalline h-BNNS as the catalyst at al ow reaction temperature (120 8 8C). According to the previously reported literatures, [11,39] the dehydrogenation process of 12H-NEC is proposed to include the adsorption of 12H-NEC on the Bsites,c leavage of the CÀHb ond and formation of H 2 gas.Weproposed that the synergistic effect of the nanoporous structure (beneficial to mass transport) and highly ordered crystalline pattern of h-BNNS (exposure of more Bsites) plays crucial role in achieving this superior dehydrogenation performance. Notably,t he catalytic efficiencyo fh -BNNS is much higher than that of Pd-, Pt-, Ru-loaded heterogeneous catalysts previously reported (Table S1).…”

“…h-BN structures are characterized by their excellent thermal and chemical stability,a nd unique electronic and optical properties,w hich are widely applied in the field of energy storage and transformation. [11,12] Although both bulk h-BN and BNNT exhibited analogous product distributions,B NNT showed ar ate of propane consumption more than one order of magnitude higher than that of h-BN,p artially because of the higher surface area of BNNT (97 m 2 g À1 )relative to bulk h-BN (16 m 2 g À1 ), and thus as uperior mass transfer effect during the catalytic process. [2,[8][9][10] To date,H ermans et al reported that bulk h-BN and boron nitride nanotubes (BNNT) exhibited unique and highly efficient catalytic properties for the oxidative dehydrogenation of propane,resulting in great selectivity to olefins (79 % propene and 12 %e thene at 14 %p ropane conversion).…”

Carbon‐Doped BN Nanosheets for the Oxidative Dehydrogenation of Ethylbenzene

“…[9] Nevertheless,b ecause of high in-plane mechanical strength and good chemical inertness even at elevated temperatures, [10] h-BN keeps stable up to 1000 8 8Cinair, 1400 8 8Cinvacuum, and 2800 8 8Ci na ni nert atmosphere,w hich is highly desirable in the aerobic oxidation reaction. [9] Nevertheless,b ecause of high in-plane mechanical strength and good chemical inertness even at elevated temperatures, [10] h-BN keeps stable up to 1000 8 8Cinair, 1400 8 8Cinvacuum, and 2800 8 8Ci na ni nert atmosphere,w hich is highly desirable in the aerobic oxidation reaction.…”

Graphene-like boron nitride anchored Brönsted acid ionic liquids as metal-free catalyst for advanced oxidation process

“…Compared with graphene, G-h-BN holds better thermal-stability and resistance to chemical corrosion. Indeed, G-h-BN has been widely employed as supports for synthesizing heterogeneous catalysts with excellent catalytic activity and promising durability [30][31][32][33][34][35][36].…”