Influence of the defects on selective hydrogenation of cinnamaldehyde to cinnamyl alcohol over UiO-66 supported Pt catalysts

UiO-66 supported metal catalysts have shown high catalytic activity and selectivity to cinnamyl alcohol (COL) in the selective hydrogenation (SHYD) of cinnamaldehyde (CAL), but the roles of missing-linker defects (MLDs) in UiO-66 on the catalytic performance of the UiO-66 supported metal catalysts have less been reported. Here, UiO-66 supports with the different amount of MLDs were used as the supports, and three series of UiO-66 supported Pt (Pt/U) catalysts were prepared by sol-impregnation, wet-impregnation as well as in-situ encapsulation methods, respectively. The influences of the MLDs in UiO-66 on the catalytic properties of the prepared Pt/U catalysts in the SHYD of CAL were investigated. The series of Pt/U-720 catalysts with the more MLDs showed higher CAL conversion and selectivity to COL than the corresponding Pt/U-F catalysts with fewer MLDs. The different preparing methods affect the location and dispersion of Pt species on UiO-66 supports and the metal-support interaction, but the location of the supported Pt species on UiO-66 is the critical factor affecting the catalytic properties of Pt/U catalysts. The presence of the MLDs in UiO-66 is the key to preparing UiO-66 supported Pt catalysts with high SHYD performance.