Engineering O-O Species in Boron Nitrous Nanotubes Increases Olefins for Propane Oxidative Dehydrogenation.

Boron nitride (BN) has been widely studied as an efficient catalyst for oxidative propane dehydrogenation (OPDH). Oxygen-containing boron species (e.g., BO·, B()O) are generally considered as the active centers in BN for OPDH. Here, we show an effective progressive substitution strategy toward the development of boron-oxygen-nitrogen nanotubes (BONNTs) enriched with O-O species as a highly active, selective, and stable catalyst for OPDH. At 525 °C, an olefin yield of 48.6% is achieved over BONNTs with a propane conversion of 64.4%, 2.8 times that of boron nitrogen nanotubes (BNNTs). Even after reaction for 150 h (475 °C), BONNTs exhibit good olefin yield. Both the B()O and O-O species that coexist in the BONNT catalyst are demonstrated as active centers, which differs from the B()O one in BNNTs. Based on catalytic results, propane and oxygen alternate treatment experiments, and theoretical calculations, the O-O center is more favorable for producing both propylene (C) and ethylene (C), which experiences a dehydration pathway and two possible reaction paths with a lower energy barrier to yield olefins, while B()O is mainly responsible for producing few C.