The effect of MgO in Pd/Al₂O₃-MgO catalyst on a selective hydrogenation reaction

Selective hydrogenation is a significantly important catalytic process in many industrial processes, where Pd-based catalysts are the most commonly used. Herein, the surface properties of gamma-Al2O3 were modified by the layered flower-like architectures of alkaline MgO using a simple hydrothermal method. Then, a series of Pd/Al2O3-MgO catalysts were prepared by an incipient wetness impregnation method for the selective hydrogenation of isoprene. The results showed that the Pd/Al2O3-0.12MgO catalyst exhibited superior catalytic performance with a high activity (93%) and high selectivity (99%) for the semi-hydrogenation products. Systematic studies have demonstrated that the support effect plays an important role in dispersing and stabilizing palladium particles. The reasons for the improved catalytic performance were attributed to the high dispersion of Pd nanoparticles, the changed electronic structure of Pd, and the strong interaction between Pd nanoparticles and supports. This work opens a simple route to regulate the electronic properties of active metal sites via support modification for selective hydrogenation reactions.