Carbon-supported Pd nanoparticles have been proved to be efficient dual hydrogenation–oxidation nanocatalysts in both the selective aqueous oxidation of benzyl alcohol and the hydrogenation of furfural in water under microwave irradiation. Nanocatalysts based on trioctylphosphine and triphenylphosphine-stabilized-Pd NPs on oxidized carbon support were found to be the most active. The presence of oxygen groups on the surface of the carbon support, particularly those of acidic character, improve the Pd NPs immobilization as well as the water affinity, and consequently the catalytic performances of the system.