Promoting Catalytic Activity of Boron by Phosphor in Propane Oxidative Dehydrogenation

Metal-free boron-containing materials show excellent performance in the oxidative dehydrogenation of propane (ODHP) reaction, while it remains unclear how the composition of the materials may influence their catalytic activity. Herein, by using boron phosphide (BP) as the test bed, a density functional theory study of the influences of P atoms in the backbone and the extent of surface oxidation on the catalytic activity was reported to address the structure-catalytic activity relationship in the ODHP reaction. The calculations show that (1) the P element in BP may influence the composition of the occupied states of BP (P, 47.3%; O, 98.8%; and N, 81.7%) and bring significant impact on its properties. The influence of O in the B2O3 (O) and N in the h-BN (N) was also analyzed for comparison. (2) The more oxidized surface (BP-H) is more reactive than the less oxidized surface (BP-L) in view of the lower free-energy barrier to the rate-determining step (45.8 vs 57.3 kcal/mol for the dehydrogenation of propane step, respectively). This study explains the role of the P element and the effect of surface oxidation and provides a comprehensive understanding of the structure-activity relationship of boron-containing materials in ODHP.