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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Convective mass transport in ionic liquids studied by electrochemical and electrohydrodynamic impedance spectroscopy

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Torresi, Roberto M. [1] ; Lodovico, Lucas [1] ; Benedetti, Tania M. [1] ; Alcantara, Maria R. [1] ; Debiemme-Chouvy, Catherine [2] ; Deslouis, Claude [2]
Total Authors: 6
[1] Univ Sao Paulo, Inst Quim, BR-05513970 Sao Paulo - Brazil
[2] Univ Paris 06, LISE UPR CNRS 15, F-75252 Paris - France
Total Affiliations: 2
Document type: Journal article
Source: Electrochimica Acta; v. 93, p. 32-43, MAR 30 2013.
Web of Science Citations: 5

In this work, the role of convective mass transport in two ionic liquids (ILs) that differ by the anions 1-butyl-2,3-dimethyl-imidazolium bis(trifluoromethanesulfonyl)imide ({[}BMMI]{[}Tf2N]) and 1-butyl-2,3-dimethyl-imidazolium tetrafluorborate ({[}BMMI]{[}BF4]) were studied in the presence of ferrocene (Fe) as a redox tracer. A rotating disk electrode (RDE) system was used, and the use of electrochemical (EIS) and electrohydrodynamic (EHD) impedance spectroscopies allowed for a deeper analysis of mass transport and charge transfer at the surface of the electrode. The two ILs showed a viscoelastic character that was observed using a parallel plate geometry viscometer with a high storage-to-loss modulus ratio in a frequency domain where the RDE response was characterized by significant elongational flow kinematics. As a general conclusion, the observed effects were interpreted as unbalanced contributions of the elongational flow close to the electrode surface, which induced an anisotropic diffusivity that increased along the flow lines, and the effect of Fc and Fc(+) as structure breakers or strengtheners in the diffusion layer. Finally, from EIS analysis, it was established that increasing the overpotential in the anodic direction yielded an increased Schmidt number, which indicated a detrimental effect on the mass transport of Fc(+), whose production rate was also increased under the same conditions. EIS showed that the anion had an effect on the reaction rate of Fc oxidation and on the double-layer capacitance value. (C) 2013 Elsevier Ltd. All rights reserved. (AU)

FAPESP's process: 09/53199-3 - Molecular recognition and energy storage: fundamental studies concerning geometry, size and synthesis effects on the optimization of the chemical properties of electroactive materials
Grantee:Roberto Manuel Torresi
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 12/02117-0 - Poly(ionic liquids) in electrochemical devices: polyelectrolytes for energy storage and conversion devices and stabilization of graphene and poly(3,4-etylenedioxidethiophene) (PEDOT) for electroactive films obtention
Grantee:Tania Machado Benedetti
Support Opportunities: Scholarships in Brazil - Post-Doctoral
FAPESP's process: 11/16078-3 - Graphene electrochemistry in ionic liquids
Grantee:Lucas Lodovico de Carvalho
Support Opportunities: Scholarships in Brazil - Master