Electrochemical Hydrogen Oxidation on Pt(110): A Combined Direct Molecular Dynamics/Density Functional Theory Study

A first-principles direct molecular dynamics and density functional theory study of the electrooxidation of molecular hydrogen at the Pt(110)/water interface was conducted to gain an atomic-level understanding of the electrocatalytic processes and of adsorbed reaction intermediates. The H2 electrooxidation follows the Tafel−Volmer mechanism—a homolytic H−H bond cleavage and formation of adsorbed terminal hydrogen atoms atop the topmost platinum, followed by oxidation of the adsorbed reaction intermediates. Potential-dependent activation energies computed for the hydrogen redox reactions were employed to predict the Tafel plot for hydrogen electrooxidation. The theoretically predicted Tafel plot is in very good agreement with experiment in support of the Tafel−Volmer mechanism for the Pt(110) surface.