▎ 摘　　要

Doping of porous carbon materials with metallic atoms, clusters and nanoparticles is viewed as a way to enhance the hydrogen storage in those materials. Transition metals are dopants of interest. For this reason we present a theoretical study of the interaction of molecular hydrogen with small palladium clusters (Pd-n, n = 1-6) supported on a graphene layer. The adsorption of H-2 on those supported Pd clusters leads to two types of adsorption states. The simplest one is an activated state of the hydrogen molecule, with the H-H distance stretched and the H-H bond weakened, but not broken. Adsorption in the activated states occurs with no barriers and the binding energies are in a range of values of interest for achieving a favorable reversible hydrogen storage in the doped material. The second type is a dissociated and chemisorbed state, with the separated hydrogen atoms attached to the Pd cluster. The dissociative chemisorption states are more stable than the activated states. However, starting with Pd-4, there are barriers for the dissociative chemisorption of H-2, and the heights of those energy barriers are a few tenths of an electronvolt.