MOF-derived bimetallic NiCo nanoalloys for the hydrogenation of biomass-derived levulinic acid to γ-valerolactone

Abstract

The selective hydrogenation of biomass-derived levulinic acid (LA) to γ-valerolactone (GVL) is one of pivotal reactions in many of the biorefinery schemes for the production of value-added chemicals and biofuels. Herein, we have fabricated carbon-supported bimetallic NiCo catalysts based on the metal–organic framework (MOF) material via a pyrolysis method. The as-obtained Ni₁Co₁ bimetallic catalyst outperforms monometallic counterparts in the catalytic performance of LA-to-GVL, with a nearly full conversion of LA and a GVL yield of 95.2%, in particular with an excellent catalyst stability up to seven consecutive runs at 160°C and 4 MPa H₂. Based on a combined characterization study by employing advanced techniques, for example, extended x-ray absorption fine structure (EXAFS), high-angle annular dark-field scanning transmission electron microscopy (HADDF-STEM), and electron paramagnetic resonance (EPR), we reveal that the enhanced catalytic performance, in particular the excellent stability, could be attributed to the formation of the bimetallic alloys, which efficiently alleviates the metal leaching and sintering during catalysis.