A series of Pd nanoparticles deposited on the SiO2 support were facilely and successfully synthesized in the presence of the green solvent CO2, where the uniform distribution of Pd with small particle size was successfully achieved. The resulting Pd/SiO2 nanoparticles catalysts exhibited excellent catalytic performances in the selective hydrogenation of biomass-derived levulinic acid, showing close to perfect selectivity of biofuel gamma-valerolactone with the TON of 884.7 at 97.3% conversion of levulinic acid. The catalytic performance was superior to the activities of the 5 wt% Pd/SiO2 nanoparticle catalyst prepared by the traditional impregnation method. Besides, the reaction parameters (e.g., the Pd loading, reaction time, reaction temperature, and hydrogen pressure), catalyst stability and reaction mechanism on the hydrogenation performance were studied. The resulting Pd nanoparticles catalysts behaved high stability in the hydrogenation. (C) 2013 Elsevier B.V. All rights reserved.