Surface characterization of platinum electrodes

Research output: Contribution to journalArticle

Authors

  • José Solla-Gullón
  • Paramaconi Rodríguez
  • Enrique Herrero
  • Antonio Aldaz
  • Juan M. Feliu

Colleges, School and Institutes

External organisations

  • Instituto de Electroquímica
  • Universidad de Alicante

Abstract

The quantitative analysis of the different surface sites on platinum samples is attempted from pure voltammetric data. This analysis requires independent knowledge of the fraction of two-dimensional (111) and (100) domains. Specific site-probe reactions are employed to achieve this goal. Irreversibly-adsorbed bismuth and tellurium have been revealed to be sensitive to the presence of (111) terrace domains of different width whereas almost all sites involved in (100) ordered domains have been characterized through germanium adatoms. The experimental protocol follows that used with well-defined single-crystal electrodes and, therefore, requires careful control of the surface cleanliness. Platinum basal planes and their vicinal stepped surfaces have been employed to obtain calibration plots between the charge density measured under the adatom redox peak, specific for the type of surface site, and the corresponding terrace size. The evaluation of the (100) bidimensional domains can also be achieved using the voltammetric profiles, once the fraction of (111) ordered domains present in the polyoriented platinum has been determined and their featureless contribution has been subtracted from the whole voltammetric response. Using that curve, it is possible to perform a deconvolution of the adsorption states of the polycrystalline sample different from those related to (111) domains. The fraction of (100)-related states in the deconvoluted voltammogram can then be compared to that expected from the independent estimation coming from the charge involved in the redox process undergone by the irreversibly-adsorbed germanium and thus check the result of the deconvolution. The information about the surface-site distribution can also be applied to analyze the voltammetric profile of nanocrystalline platinum electrodes.

Details

Original languageEnglish
Pages (from-to)1359-1373
Number of pages15
JournalPhysical Chemistry Chemical Physics
Volume10
Issue number10
Early online date25 Oct 2007
Publication statusPublished - 1 Jan 2008