Efficient cobalt-catalyzed transfer hydrogenolysis of lignin-related compounds using formic acid

Abstract

Cleaving the C–O bond is crucial for lignin valorization, a key biomass component. This study reports the synthesis and characterization of cobalt- and zinc-based catalysts, demonstrating high efficiency in the catalytic transfer hydrogenolysis of lignin-derived molecules using formic acid as the hydrogen source without the need for an added base like triethylamine. Depending on the thermal treatment, the materials exhibited different catalytic activities. For the material treated at 800 °C, cobalt nanoparticles were primarily observed, while at 1000 °C, no nanoparticles were detected; however, both catalysts were active in hydrogen production and in the hydrogenolysis of model molecules. We propose that cobalt species, ranging from nanometric to atomic scale, are responsible, with nitrogen-coordinated cobalt playing a critical role. The catalysts were also evaluated for their performance in the catalytic dehydrogenation of formic acid, a key step in hydrogen production. Findings indicate that carbon monoxide formation may contribute to the reduced activity observed in hydrogenolysis.