Gohda Yoshihiro, Schnur Sebastian, Gross Axel
Institute for Theoretical Chemistry, Ulm University, Ulm D-89069, Germany.
Faraday Discuss. 2008;140:233-44; discussion 297-317. doi: 10.1039/b802270d.
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.
我们使用广义梯度近似下的密度泛函理论，研究了在水和离子存在的情况下分子与Pt(111)相互作用的简单反应路径。我们特别关注H₂和O₂在Pt(111)上的解离，它们分别代表析氢/氧化反应和氧还原反应中的重要反应步骤。由于水与Pt(111)的相互作用较弱，Pt电极的电子结构几乎不会受到水的存在的干扰。因此，直接在电极表面发生的过程，如特定吸附或从化学吸附的分子氧状态解离氧，仅受到水的微弱影响。相比之下，远离电极发生的过程，如H₂的解离，可以通过分子与水的直接相互作用而被水环境改变。
