Formation of an Amorphous LaAlBO_x Overlayer on Crystalline LaAlO₃ Perovskite for Highly Efficient and Stable Propane...

Supported boron oxide catalysts have demonstrated ultra-high selectivity in the oxidative dehydrogenation of propane (ODHP), but their practical deployment is severely limited by poor thermal stability and rapid deactivation, primarily due to the hydrolysis of active B-O sites forming volatile boric acid. Here, we develop a catalyst comprising a crystalline LaAlO₃ (LAO) perovskite coated with an amorphous LaAlBO_x overlayer, achieved through the thermal treatment of physically mixed H₃BO₃ and LAO. During reaction, the amorphous LaAlBO_x overlayer grows in thickness, wherein the concurrent formation of strong M-O-B (M = La, Al) bonds effectively suppress boron volatilization, ensuring long-term structural stability. The optimized catalyst achieves a propylene yield of 21% and a total olefin selectivity of 97% during continuous operation at 500°C for 100 h, which ranks among the top-tier performance reported in the literature. Density functional theory (DFT) calculations demonstrate that the formation of M-O-B bonds not only stabilizes boron species from volatilization but also lowers the energy barrier of the rate-determining-step in ODHP, thereby leading to remarkable catalytic performance. Importantly, this strategy is found to be extendable to other perovskites (e.g., SmAlO₃, SrTiO₃, BaTiO₃), underscoring its generality for designing durable boron‑based catalysts.