Atomistic calculations of hydrogen loading in palladium

Abstract Hydrogen loading on nanometer-size palladium clusters and defect crystals are simulated by the Monte Carlo method. The pressure-composition isotherms are calculated. In contrast with simulations of bulk samples, the clusters show no evidence of a phase transformation. Simulation shows that hydrogen is loaded on the surface first and then the interior of the cluster. This behavior is related to the observed narrowing of the plateau in the phase boundary of the pressure-composition phase diagram of nanocrystalline palladium.