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

Abstract

We have studied the hydrogen oxidation reaction on various catalytic sites at the water/Pt(100) interface with first-principles direct molecular dynamics and minimum energy pathway calculations. The calculations indicate that the mechanism for electro-oxidation of H 2 on terrace sites of the Pt(100) surface depends on the concentration of inactive adsorbed hydrogen on the electrode surface. Near the reversible potential, the electro-oxidation follows the Tafel-Volmer homolytic cleavage of H 2 at low coverage of adsorbed hydrogen. If the surface is covered with ca. 1 monolayer of hydrogen, however, the oxidation proceeds by the Heyrovsky-Volmer mechanism. We found good agreement between measured and predicted Tafel plots, indicating that hydrogen oxidation/reduction reaction on Pt(100) takes place via the Heyrovsky-Volmer mechanism under ca. 1 monolayer coverage of inactive adsorbed hydrogen.

Real-World Predictions from Ab Initio Molecular Dynamics Simulations

“…Examples are the oxidation and evolution of hydrogen on different transition metal surfaces, the reduction of oxygen on several surfaces as well as carbon monoxide reactions, and a complex photoactive reaction in a solar cell. Hydrogen under electrochemical conditions was investigated very recently [222,223]. Santana et al investigated the electro-oxidation of molecular hydrogen at the Pt(110)-water interface [222].…”

“…Hydrogen under electrochemical conditions was investigated very recently [222,223]. Santana et al investigated the electro-oxidation of molecular hydrogen at the Pt(110)-water interface [222]. The Tafel-Volmer mechanism with a homolytic H-H bond cleavage followed by the formation of adsorbed terminal hydrogen atoms and further oxidation of the H atoms was observed by the authors.…”

An Unusual Exchange Mechanism in the Tafel Reaction on Pt(110)‐(1×1) Surfaces

“…In electrochemical experiments it is not always clear which surface has been used . On both types of surfaces hydrogen adsorption has been well investigated by DFT . Here we shall study, how two such adsorbed atoms can combine to form molecular hydrogen, and calculate the corresponding energies of activation.…”

The charged interface between Pt and water: First principles molecular dynamics simulations

“…[12][13][14][15][16][17][18][19] The interface between a charged Pt cluster and liquid water has also been studied. 20,21 Here, we have performed first-principles molecular dynamics (FPMD) simulations for the charged interface between a Pt electrode and an aqueous solution at 353 K. [22][23][24]26 In this work, the charge is controlled by a newly developed effective screening medium (ESM) scheme. 27 First-principles simulations deepen the understanding of interface science as well as shed light on experimental observations.…”