Selective Hydrogenation Performance of Pd Catalysts Supported on Alumina Microspheres
Alumina microspheres with a lamellar-assembled flower-like morphology were synthesized via a urea-assisted hydrothermal method and used as supports to prepare Pd/Al2O3-M catalysts by incipient wetness impregnation. The catalytic performance was evaluated in the selective hydrogenation of isoprene and the hydrogenation of 2-ethylanthraquinone for hydrogen peroxide production, and compared with a commercial alumina-supported Pd catalyst (Pd/Al2O3). Characterization revealed that the flower-like structure, composed of stacked nanosheets, promoted high Pd dispersion and enhanced metal-support interaction, leading to a higher surface Pd content and more abundant active sites. Under 60 °C and 1 MPa H2, Pd/Al2O3-M achieved 95.2% conversion of isoprene with 98.3% total selectivity to isoamylenes, and exhibited good stability over 24 h. In anthraquinone hydrogenation, it reached a hydrogenation efficiency of 15.8 g/L, a 27.4% improvement over Pd/Al2O3 (12.4 g/L). The study demonstrates that modulating carrier morphology is an effective strategy to simultaneously enhance activity, selectivity, and stability of Pd catalysts, offering a promising approach for designing efficient hydrogenation catalysts.