INFIQC   05475
INSTITUTO DE INVESTIGACIONES EN FISICO- QUIMICA DE CORDOBA
Unidad Ejecutora - UE
artículos
Título:
Super-Nernstian Shifts of Interfacial Proton-Coupled Electron Transfers: Origin and Effect of Noncovalent Interactions
Autor/es:
CHRISTOPHER WILDI; GEMA CABELLO; MARTIN E. ZOLOFF MICHOFF; PATRICIO VÉLEZ; EZEQUIEL P. M. LEIVA; JUAN J. CALVETE; RAFAEL ANDREU; ÁNGEL CUESTA
Revista:
JOURNAL OF PHYSICAL CHEMISTRY C
Editorial:
AMER CHEMICAL SOC
Referencias:
Lugar: Washington; Año: 2015
ISSN:
1932-7447
Resumen:
Anions whose specific adsorption involves a proton-coupled electrontransfer (PCET) include adsorbed OH (OHad), which plays an enormously relevant rolein many fuel-cell reactions. OHad formation has often been found to happen in alkalinesolutions at potentials more negative than expected from a Nerstian shift, and this hasbeen proposed as the reason for the often easier oxidation of organic molecules in alkalinemedia, as compared to acids. Noncovalent interactions with electrolyte cations have alsobeen 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 oneelectron 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 doubleeffect: they provoke an additional shift by blocking the site of transfer but decrease thesuper-Nernstian contribution by separating the plane of transfer from the outer Helmholtz plane.