Engineering boron-terminated defects in carbon-doped boron nitride catalysts for enhanced activity in oxidative dehydrogenation of propane

Carbon-doped boron nitride (CBN) materials are a novel class of non-metallic catalysts with significant potential in catalyzing the oxidative dehydrogenation of propane (ODHP) process. ZIF-8 is a type of metal-organic framework (MOF) material featuring a zeolitic imidazolate framework (ZIF) skeleton. Boron nitride materials derived from ZIF-8 inherit its advantages, including customizable structure, tunable mesoporous properties and high specific surface area. The present work has developed a novel synthetic method to introduce and engineer the B-terminated defect in CBN-Zx through the co-pyrolysis of ZIF-8 and other typical precursors containing boron and nitrogen. The unique role of ZIF-8 precursor was to produce mesopores in CBN-Zx, which contained plenty of B-terminated defects formed via the volatilization of Zn and the elimination of C and N species during the pyrolysis process, and these defects could transform into active BO_x species, which enhanced the ODHP activity. The optimized CBN-Z0.4 catalyst exhibited high propane conversion at 23.9% in ODHP with the olefin selectivity at 86.1%, which had reached the best level among boron-based catalysts in ODHP. The present work not only provides a new idea for synthesizing highly efficient boron-based catalysts for ODHP reactions, but also sheds light on the structure-function relations, rational design and practical applications of CBN catalysts for ODHP reactions.