Molybdenum carbide nanoparticles within carbon nanotubes as superior catalysts for γ-valerolactone production via levulinic acid hydrogenation†
We report here for the first time that supported molybdenum carbide is an efficient catalyst to selectively convert levulinic acid into γ-valerolactone in the aqueous phase. We have observed that the support plays a fundamental role in the activity and stability of molybdenum carbide that is stable when supported in carbon nanotubes but undergoes deactivation when supported on activated carbon. Particularly, when the carbide nanoparticles are positioned within the carbon nanotubes, conversion and selectivity values higher than 99 and 90%, respectively, were observed at 30 bar of H2 and 200 °C using a continuous-flow trickle-bed reactor. In a turnover frequency (TOF) basis, these values are similar to those obtained for a ruthenium catalyst evaluated under the same conditions.