Pd-Ni-Fe Nanoparticles Supported on UiO-66 for Selective Hydrogenation of Fatty Acid Methyl Esters to Alcohols

Multimetallic catalysis generally involves synergistic effects in chemical transformations that can significantly improve catalytic performance, and the loading of metal nanoparticles (MNPs) onto porous materials contributes to increase the number of active sites. Herein, we investigated the selective hydrogenation of methyl palmitate (MP) using a series of transition MNPs Pd-Ni-Fe with varying molar ratios supported on UiO-66. The catalysts were synthesized through a straightforward liquid-phase impregnation-reduction method. Compared with Pd-Ni/UiO-66, the addition of Fe into Pd-Ni/UiO-66 was found to significantly enhance the selectivity of the desired product, alcohols. This improvement could be attributed to the oxophilic nature of Fe, which weakens the adsorption strength of carbon, thereby increasing the cleavage of the C-O bond rather than the C-C bond. The optimal combination was determined to be Pd1Ni2Fe6/UiO-66, resulting in a 99% conversion of MP and exhibiting 96% selectivity toward 1-hexadecanol. Notably, the catalyst exhibited versatility and stability in the hydrogenation process of fatty acid methyl esters while also offering the advantage of easy separation and reusability. Finally, the reaction mechanism and pathway were proposed based on the product distribution and the properties of the transition MNPs.