Super-Nernstian Shifts of Interfacial Proton-Coupled Electron Transfers: Origin and Effect of Noncovalent Interactions
| Autor: | Christopher S. Wildi, Patricio Vélez, Angel Cuesta, Gema Cabello, Ezequiel P. M. Leiva, Juan José Calvente, Martin E. Zoloff Michoff, Rafael Andreu |
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| Přispěvatelé: | Universidad de Sevilla. Departamento de Química Física, Universidad Nacional de Córdoba |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
chemistry.chemical_classification
Proton Inorganic chemistry 02 engineering and technology Electron Electrolyte 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Organic molecules Metal Electron transfer General Energy Adsorption chemistry Chemical physics visual_art visual_art.visual_art_medium Non-covalent interactions Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | idUS. Depósito de Investigación de la Universidad de Sevilla instname |
| Popis: | Anions whose specific adsorption involves a proton-coupled electron transfer (PCET) include adsorbed OH (OHad), which plays an enormously relevant role in many fuel-cell reactions. OHad formation has often been found to happen in alkaline solutions at potentials more negative than expected from a Nerstian shift, and this has been proposed as the reason for the often easier oxidation of organic molecules in alkaline media, as compared to acids. Noncovalent interactions with electrolyte cations have also been shown to affect the stability of OHad. Using cyanide-modified Pt(111) as a model, we show here that interfacial PCETs will show a super-Nernstian shift if (i) less than one electron per proton is transferred and (ii) the plane of proton-electron transfer and that of the metal surface do not coincide. We also show that electrolyte cations have a double effect: they provoke an additional shift by blocking the site of transfer but decrease the super-Nernstian contribution by separating the plane of transfer from the outer Helmholtz plane. Universidad Nacional de Córdoba CONICET- PIP 11220110100992, PICT 2012-2324, PME 2006-01581 |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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