Hydrogen Storage Properties of Nanoporous Palladium Fabricated by Dealloying

Abstract

The hydrogen storage properties of nanoporous Pd fabricated by dealloying a Pd 0.2 Co 0.8 alloy were investigated by measuring pressure−composition isotherms (PCTs). The hydrogen storage behaviors of nanoporous Pd were obviously different from those of bulk Pd and other nanostructured Pd materials, such as nanocrystalline Pd and nanoparticle Pd. The miscibility gap narrowed similarly to that in nanocrystalline or nanoparticle Pd, but the gap narrowed in a different manner; that is, the hydrogen dissolution in the α-phase of nanoporous Pd was similar to that in the α-phase of bulk Pd, while that in the β-phase of nanoporous Pd was similar to that in the β-phase of the nanostructured Pd. High-resolution transmission electron microscopy showed lattice disorder (both expansion and contraction) at the surface of nanoporous Pd. First-principles calculations within the generalized gradient approximation suggest that the lattice expansion and contraction are responsible for the hydrogen adsorption in the α-phase of nanoporous Pd.