Ru nanoclusters supported on HfO2@CN derived from NH2-UiO-66(Hf) as stable catalysts for the hydrogenation of levulinic acid to γ-valerolactone

The catalytic hydrogenation of levulinic acid to produce value-added gamma-valerolactone represents a model reaction for upgrading biomass. Herein, we report the development of Ru/HfO2@CN, a ruthenium nanocluster catalyst supported on HfO2 embedded in nitrogen-doped porous carbon (HfO2@CN) derived from a Hf-based metal-organic framework [NH2-UiO-66(Hf)], as a highly efficient and stable catalyst for this transformation under mild reaction conditions. These characteristics are mainly attributed to the HfO2 embedded within the nitrogen-doped porous carbon support, which results in a high and stable dispersion of the Ru nanoclusters and also generates acidic sites that are hypothesized to promote the hydrogenation.