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Voltammetric Scanning Electrochemical Cell Microscopy: Dynamic Imaging of Hydrazine Electro-oxidation on Platinum Electrodes.
Chen, Chang-Hui; Jacobse, Leon; McKelvey, Kim; Lai, Stanley C S; Koper, Marc T M; Unwin, Patrick R.
Afiliação
  • Chen CH; †Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K.
  • Jacobse L; ‡Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
  • McKelvey K; †Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K.
  • Lai SC; §MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
  • Koper MT; ‡Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
  • Unwin PR; †Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K.
Anal Chem ; 87(11): 5782-9, 2015 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-25942527
ABSTRACT
Voltammetric scanning electrochemical cell microscopy (SECCM) incorporates cyclic voltammetry measurements in the SECCM imaging protocol, by recording electrochemical currents in a wide potential window at each pixel in a map. This provides much more information compared to traditional fixed potential imaging. Data can be represented as movies (hundreds of frames) of current (over a surface region) at a series of potentials and are highly revealing of subtle variations in electrode activity. Furthermore, by combining SECCM data with other forms of microscopy, e.g. scanning electron microscopy and electron backscatter diffraction data, it is possible to directly relate the current-voltage characteristics to spatial position and surface structure. In this work we use a "hopping mode", where the SECCM pipet probe is translated toward the surface at a series of positions until meniscus contact. Small amounts of residue left on the surface, upon probe retraction, demark the precise area of each measurement. We use these techniques to study hydrazine oxidation on a polycrystalline platinum substrate both in air and in a deaerated environment. In both cases, the detected faradaic current shows a structural dependence on the surface crystallographic orientation. Significantly, in the presence of oxygen (aerated solution) the electrochemical current decreases strongly for almost all grains (crystallographic orientations). The results highlight the flexibility of voltammetric SECCM for electrochemical imaging and present important implications for hydrazine electroanalysis.

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Texto completo: Disponível Coleções: Bases de dados internacionais Base de dados: MEDLINE Idioma: Inglês Revista: Anal Chem Ano de publicação: 2015 Tipo de documento: Artigo País de afiliação: Reino Unido