Enhanced Electronic Interaction of BOx-La Species Suppressing Hydrolytic Leaching for Stable and Active Oxidative Dehydrogenation of Propane

Boron-based materials are promising catalysts for the oxidative dehydrogenation of propane (ODHP) but face a challenge in retaining the stability of BOx species against hydrolytic leaching. Herein, we developed a boron-based catalyst possessing graded BOx/LaBxOy/LaB3O6 multi-interfaces derived from LaB6 via a controlled surface oxidation. Multiple characterizations revealed that the active BOx-La species were hosted within the BOx/LaBxOy/LaB3O6 multi-interfaces, where significant charge transfer between B and La evidenced a strong bonding interaction between outer-layer BOx species and La species. The catalyst exhibited an olefin selectivity of 94.9% with 25.9% propane conversion at 530 °C and demonstrated long-term durability during a 1000 h test under intrinsic propane conversion, with a low deactivation rate constant (kd = 0.0004 h−1) and a slow boron leaching rate of only 0.001 wt% h−1. DFT simulations revealed that in situ-formed BOx-La species exhibited enhanced hydrolysis resistance in the presence of La, which alleviated the electron deficiency of nearby B and impeded the nucleophilic attack of H2O at the B sites. This interfacial electronic interaction preserved the active BOx species and ensured high stability under moisture-containing ODHP conditions, outperforming traditionally impregnated BOx catalysts. This work presents a facile structural design principle for developing highly stable boron-based ODHP catalysts.