We report a combined experimental and computational study on exfoliated montmorillonite (ex-MMT) nanoplatelet supported palladium catalysts.The experimental results revealed that the Pd/ex-MMT catalysts were more stable than Pd/C catalysts in an acidic environment.The results from the density functional theory (DFT) calculations revealed that the O atoms from the AlO6 octahedra in ex-MMT act as anchoring sites for Pd nanoparticles (NPs) that are strongly bound to the ex-MMT support.The partial density of state calculations indicated that the Pd-d states and the O(AlO6)-p states have similar energy.Therefore, it is very easy for electrons to transfer between these states and to form Pd-O(AlO6) bonds.In addition, the defective or destroyed SiO4 tetrahedra can be restructured directly by the O atoms from O2 molecules or indirectly by the intermediates from the reduction of O2.The DFT calculations also revealed that the defects in the ex-MMT supports provide anchor sites for the Pd catalysts to tightly bind on the ex-MMT supports.For Pds/ex-MMT,with the attacks of Oads, the Pd atoms in the Pds cluster remain linked together through a Pd-Pd bond and are anchored tightly on the ex-MMT.However, for Pd/C, the Pd atoms in the Pds cluster are not only oxidized but also separated from the carbon bulk.