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Strain and coordination effects in the adsorption on early transition metals were studied using density functional theory. We show that, in contrast to late transition metals, early transition metal surfaces with a less than half-filled local d-band exhibit lower adsorption energies upon lattice expansion and on low-coordinated sites, in agreement with predictions based on the d-band model. This demonstrates that the d-band model can be extended to early transition metals. Implications of these results for hydrogen storage materials are discussed.

We studied simple reaction pathways of molecules interacting with Pt(111) in the presence of water and ions using density functional theory within the generalized gradient approximation. We particularly focus on the dissociation of H2 and O2 on Pt(111) which represent important reaction steps in the hydrogen evolution/ oxidation reaction and the oxygen reduction reaction, respectively. Because of the weak interaction of water with Pt(111), the electronic structure of the Pt electrode is hardly perturbed by the presence of water. Consequently, processes that occur directly at the electrode surface, such as specific adsorption or the dissociation of oxygen from the chemisorbed molecular oxygen state, are only weakly influenced by water. In contrast, processes that occur further away from the electrode, such as the dissociation of H2, can be modified by the water environment through direct molecule-water interaction.

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