Phenol Catalytic Hydrogenation over Palladium Nanoparticles Supported on Metal-Organic Frameworks in the Aqueous Phase

Metal-organic frameworks (MOFs) have been extensively applied as supports in hydrogenation catalysis owing to their topological structure and high hydrogen storage capabilities. Pd nanoparticles (NPs) supported on a hollow box-shaped MOF were prepared for phenol hydrogenation in the aqueous phase. The MOF preparation modulated by monocarboxylic acids grow into different structures. MOF140-AA, modulated by acetic acid at 140 degrees C, presents the structure of regular cube with a smooth surface. Compared to other supports, Pd NPs supported on MOF140-AA presents high phenol conversion due to the high hydrogen storage capability of MOF140-AA. Phenol is completely converted to cyclohexanol over Pd/MOF140-AA reacted at 260 degrees C for 2 h with high selectivity. The reaction mechanism of phenol hydrogenation is studied by density functional theory (DFT). The phenol hydrogenation mechanism is calculated on a Pd-38 cluster, which describes the reaction pathway consistent with experimental results.