Sequential Pt(1 1 1) oxide formation in perchloric acid: An electrochemical study of surface species inter-conversion

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Título: Sequential Pt(1 1 1) oxide formation in perchloric acid: An electrochemical study of surface species inter-conversion
Autor/es: Gómez Marín, Ana María | Clavilier, Jean | Feliu, Juan M.
Grupo/s de investigación o GITE: Electroquímica de Superficies
Centro, Departamento o Servicio: Universidad de Alicante. Departamento de Química Física | Universidad de Alicante. Instituto Universitario de Electroquímica
Palabras clave: Oxide growth | Pt(111) | Water dissociation | Phase transition | Cyclic voltammetry
Área/s de conocimiento: Química Física
Fecha de publicación: 1-ene-2013
Editor: Elsevier
Cita bibliográfica: Journal of Electroanalytical Chemistry. 2013, 688: 360-370. doi:10.1016/j.jelechem.2012.07.016
Resumen: A significant number of electrocatalytic reactions take place in a potential region in which the surface of platinum is partly covered by oxygenated species. Hence, the mechanism of the electrochemical formation and reduction of surface oxides is fundamental to understand how its properties can determine the reactivity of the catalyst. In this paper, the dynamic of the initial states of the electrochemical oxide growth on Pt(1 1 1), in the absence of anion specific adsorption and keeping surface stability, is studied by employing electrochemical techniques. Several species, such as chemisorbed hydroxide and oxygen, initial Pt oxide structures and even sub-surface oxygen, interconvert and interact. Their existences depend more strongly on the total surface coverage than on the electrode potential. Considering structural and thermodynamic data related to the identity of the electrochemical oxide film at platinum, the results suggest that Pt(1 1 1) oxide starts by water dissociation to OHads followed by its electrochemical oxidation to Oads at higher potentials. The latter process occurs as a phase transition through a nucleation and growth mechanism, until a stable adlayer is formed. In parallel, Oads transforms to an initial Pt oxide structure. Thus, there are at least two types of processes involved in the growth of the surface oxide layer (i.e. two states of oxide films), and the separation between anodic and cathodic j–E profiles reflects a true hysteresis arising from a change of state of the surface oxide film.
Patrocinador/es: This study has been carried out in the framework of the European Commission FP7 Initial Training Network “ELCAT”, Grant Agreement No. 214936-2. Support from the Spanish MICYNN though Project CTQ2010-16271 and GV through PROMETEO/2009/045 (FEDER) are greatly acknowledged.
ISSN: 1572-6657 (Print) | 1873-2569 (Online)
DOI: 10.1016/j.jelechem.2012.07.016
Idioma: eng
Tipo: info:eu-repo/semantics/article
Revisión científica: si
Versión del editor:
Aparece en las colecciones:INV - EQSUP - Artículos de Revistas

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