Diatomite-supported Pd–M (M = Cu, Co, Ni) bimetal nanocatalysts for selective hydrogenation of long-chain aliphatic esters

Diatomite supported Pd–M (M = Cu, Co, Ni) bimetal nanocatalysts with various metal compositions were prepared and characterized by means of X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was demonstrated that the metal nanoparticles were uniformly distributed on the support, and their size was centered around 8 nm with a relatively narrow size distribution. The catalysts were used to catalyze hydrogenation of long-chain aliphatic esters, including methyl palmitate, methyl stearate, and methyl laurate. It was indicated that the all diatomite-supported Pd-based bimetal catalysts were active to the selective hydrogenation of long-chain esters to corresponding alcohols at 270 °C, originated from the synergistic effect between the metal particles and the diatomite support. For the selective hydrogenation of methyl palmitate, Pd–Cu/diatomite with metal loading of 1% and Pd/Cu = 3 displayed the highest performance, giving a 1-hexadecanol yield of 82.9% at the substrate conversion of 98.8%.

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► Diatomite-supported Pd-based bimetal nanocatalysts with various metal compositions were prepared.
► The catalysts were applied in the selective hydrogenations of long-chain esters.
► The influences of metal composition and support on the ester hydrogenation were investigated.
► The 1%Pd–Cu(3:1)/diatomite catalyst displayed the highest performance for selective hydrogenation of methyl palmitate.