Pd‐Nanocomposites Formed by Calcination of [Pd(2‐pymo) 2 ] n Framework as Catalysts of Phenylacetylene Semihydrogenation in Water

New Palladium - ZrO2 Nano-Architectures from Thermal Transformation of UiO-66-NH2 for Carbonylative Suzuki and Hydrogenation Reactions

The new nanocomposites, Pd/C/ZrO₂ , PdO/ZrO_2, and Pd/PdO/ZrO₂ , were prepared by thermal conversion of Pd@UiO-66-Zr-NH₂ (MOF) in nitrogen or air atmosphere. The presence of Pd nanoparticles, uniformly distributed on the ZrO₂ or C/ZrO₂ matrix, was evidenced by transmission electron microscopy, scanning electron microscopy (SEM), Raman and X-ray Photoelectron Spectroscopy (XPS) methods. All pyrolysed composites retained the shape of the MOF template. They catalyze carbonylative Suzuki coupling under 1 atm CO with an efficiency significantly higher than the original Pd@UiO-66-Zr-NH₂ . The most active PdO/ZrO₂ composite, formed benzophenone with TOF up to 1600 h^-1 , while by using Pd@UiO-66-Zr-NH₂ , much lower TOF values, 51-95 h^-1 , were achieved. After the reaction, PdO/ZrO₂ was recovered with the same composition and catalytic activity. Very good results were also obtained in the transfer hydrogenation of benzophenones to alcohols with Pd/C/ZrO₂ and PdO/ZrO₂ catalysts under microwave irradiation.

Highly selective hydrogenation of aromatic ketones to alcohols in water: effect of PdO and ZrO2

Pd/ZrO2 and PdO/ZrO2 composites, containing Pd or PdO nanoparticles, were prepared using an original one-step methodology. These nanocomposites catalyze the hydrogenation of acetophenone (AP) at 1 bar and 10 bar of H2 in an aqueous solution. Compared to unsupported Pd or PdO nanoparticles, a remarkable increase in their activity was achieved as a result of interaction with zirconia. An unsupported PdO hydrogenated AP mainly to ethylbenzene (EB), while excellent regioselectivity towards 1-phenylethanol (PE) was obtained with PdO/ZrO2 and it was preserved during recycling. Similarly, regioselectivity to PE was higher with Pd/ZrO2 compared to unsupported Pd NPs. PdO and zirconia resulted in high selectivity to alcohols in the hydrogenation of substituted acetophenones.