Highly dispersed palladium nanoparticles (Pd NPs) encapsulated in the mesoporous cages of amine -functionalized metal-organic frameworks (MOFs) MIL-101(Cr)-NH2 have been prepared using an anion-exchange method. The Pd NPs were characterized by powder X-ray diffraction, N-2 adsorption, CO chemisorption, transmission electron microscopy, inductively coupled plasma atomic emission spectroscopy, and X-ray photoelectron spectroscopy. The particles size (2.49 nm) of the obtained Pd NPs was in good agreement with the cage diameters (2.9 nm and 3.4 nm). The resulting Pd/MIL-101(Cr)-NH2 catalysts exhibited extremely high catalytic activities in the dehalogenation of aryl chlorides in water under mild conditions. Moreover, the Pd NPs confined in mesoporous cages is easily recoverable and can be reused several times without leaching and loss of activity. (C) 2012 Elsevier Inc. All rights reserved.