Large amplitude Fourier transformed AC voltammetric investigation of the active state electrochemistry of a copper/aqueous base interface and implications for electrocatalysis

Shiddiky, Muhammad J. A ., O’Mullane, Anthony P., Zhang, Jie, Burke, L. Declan and Bond, Alan M. (2011) Large amplitude Fourier transformed AC voltammetric investigation of the active state electrochemistry of a copper/aqueous base interface and implications for electrocatalysis. Langmuir, 27 16: 10302-10311. doi:10.1021/la2017819


Author Shiddiky, Muhammad J. A .
O’Mullane, Anthony P.
Zhang, Jie
Burke, L. Declan
Bond, Alan M.
Title Large amplitude Fourier transformed AC voltammetric investigation of the active state electrochemistry of a copper/aqueous base interface and implications for electrocatalysis
Journal name Langmuir   Check publisher's open access policy
ISSN 0743-7463
1520-5827
Publication date 2011-08-16
Sub-type Article (original research)
DOI 10.1021/la2017819
Open Access Status
Volume 27
Issue 16
Start page 10302
End page 10311
Total pages 10
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Abstract The higher harmonic components available from large-amplitude Fourier-transformed alternating current (FT-ac) voltammetry enable the surface active state of a copper electrode in basic media to be probed in much more detail than possible with previously used dc methods. In particular, the absence of capacitance background current allows low-level Faradaic current contributions of fast electron-transfer processes to be detected; these are usually completely undetectable under conditions of dc cyclic voltammetry. Under high harmonic FT-ac voltammetric conditions, copper electrodes exhibit well-defined and reversible premonolayer oxidation responses at potentials within the double layer region in basic 1.0 M NaOH media. This process is attributed to oxidation of copper adatoms (Cu*) of low bulk metal lattice coordination numbers to surface-bonded, reactive hydrated oxide species. Of further interest is the observation that cathodic polarization in 1.0 M NaOH significantly enhances the current detected in each of the fundamental to sixth FT-ac harmonic components in the Cu*/Cu hydrous oxide electron-transfer process which enables the underlying electron transfer processes in the higher harmonics to be studied under conditions where the dc capacitance response is suppressed; the results support the incipient hydrous oxide adatom mediator (IHOAM) model of electrocatalysis. The underlying quasi-reversible interfacial Cu*/Cu hydrous oxide process present under these conditions is shown to mediate the reduction of nitrate at a copper electrode, while the mediator for the hydrazine oxidation reaction appears to involve a different mediator or active state redox couple. Use of FT-ac voltammetry offers prospects for new insights into the nature of active sites and electrocatalysis at the electrode/solution interface of Group 11 metals in aqueous media.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2012 Collection
Australian Institute for Bioengineering and Nanotechnology Publications
 
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Created: Thu, 17 Nov 2011, 19:14:33 EST by Dr Muhammad J. A. Shiddiky on behalf of Aust Institute for Bioengineering & Nanotechnology