Hydrogen spillover on Ni@Graphene enables robust and efficient catalytic hydrogenation of aqueous levulinic acid to γ-valerolactone.

Hydrogenation of biomass-derived aqueous levulinic acid (LA) to produce γ-valerolactone (GVL) is a promising approach from biomass to sustainable platform chemicals. However, the practical application of this method is limited because aqueous LA is highly corrosive to metal-based hydrogenation catalyst in high-temperature hydrothermal environments. Herein, we encapsulated metallic Ni0 particles with a few layers of graphene using a hydrothermal carbon coating method to obtain Ni@FLG-600 catalyst, which exhibited efficient catalytic activity and excellent cycling stability for the hydrogenation of aqueous LA to GVL. The defect-rich graphene shell prevents the Ni0 from acid corrosion meanwhile selectively permits the passage of small H 2 molecules. The resulted active H* on Ni0 spills over to the outer surface of graphene shell and reacts with LA. Remarkably, the amount of H* on graphene shell can be the descriptor of activity. This finding presents a new strategy for the fabrication of acid-resistant catalysts for aqueous biomass hydrogenation. [Display omitted] • Ni@FLG-600 is synthesized for aqueous hydrogenation of LA to GVL. • Ni0 encapsulated in a few layers of graphene is hydrothermally stable. • The Ni@FLG-600 catalyst can be reused twenty times without deactivation. • H 2 passes through the defects in the graphene shell and is activated to H* on Ni0. • H* spills over to the graphene surface to react with LA. [ABSTRACT FROM AUTHOR]