Synthesis of mesoporous Al 2 O 3 microspheres via hydrogen bond-enhanced monomicelle assembly strategy

Spherical porous alumina (Al2O3) materials hold critical importance in industrial catalysis, but their direct synthesis remains a significant challenge. Herein, we report a hydrogen bond-enhanced monomicelle assembly strategy for synthesizing uniformly monodispersed mesoporous Al2O3 microspheres. This synthesis features the introduction of glycerol with abundant hydroxyl groups (−OH) to form the hydrogen bond network between the alumina-based monomicelles. The hydrogen bond network reduces the crosslinking rate of the Al2O3 oligomers and matches it with the micelle assembly rate, thereby enabling the direct synthesis of mesoporous Al2O3 microspheres in solution. The resultant mesoporous Al2O3 microspheres exhibit uniform spherical morphology (~1.3 μm), a high specific surface area (144 m2 g-1), a large pore size (~7.8 nm), and abundant Lewis acid sites. Moreover, this strategy is universal for organic and inorganic Al2O3 precursors, overcoming the limitations of precursor compatibility. The mesoporous Al2O3 microspheres loaded with uniformly distributed PtSn nanoparticles are utilized as a highly efficient catalyst for propane dehydrogenation to propylene. The catalyst exhibits high propane conversion rate (~41%), high selectivity to propylene (>98%), a low deactivation rate constant (0.004 h-1) and remarkable long-term stability (~200 h) under industrial conditions at 550°C.