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E u r o S c i C o n C o n f e r e n c e o n
Nanotechnology &
Smart Materials
Nano Research & Applications
ISSN 2471-9838
O c t o b e r 0 4 - 0 6 , 2 0 1 8
Am s t e r d a m , N e t h e r l a n d s
Nanotechnology & Smart Materials 2018
Page 76
D
etermination of heterogeneous rate constants of redox reactions or charge
transfer resistances always involves ambiguities due to participation in double
layer (DL) capacitances and solution resistances. The rate constants determined
by the steady-state voltammograms at ultra-microelectrodes are inconsistent with
time-dependent voltammograms, implying participation of the DL impedance. We
examine controlling variables of DLs by paying attention to frequency-dependence
of the capacitance on the basis of definition of the current and the capacitance.
The capacitance is obeyed by the power law of the frequency. It is controlled by
orientation of limited amount of solvent dipoles, independent of salts. Redox
species, of which dipoles are oriented oppositely to the solvent dipoles, decrease
theDLcapacitanceandmake thevaluenegativeat highconcentrationof thespecie.
The decrease in the capacitance increases the real impedance, as predicted from
the phase angle, yielding a extra resistance. This may be a ghost charge transfer
resistance. However, there are a number of actually well-defined charge transfer
resistances, which are observed as transferring rates through films on electrodes.
This logic will be explained step-by-step by tracing the six sections: difference in
heterogeneous rate constants by steady-state and fast voltammetry; frequency-
dependent double layer impedance; variables of determining DL impedance; origin
of the frequency dependence; DL impedance complicated by diffusion-controlled
current of redox reactions; redox reaction of unanticipatedly adsorbed redox
species
Biography
Jingyuan Chen has completed her PhD fromUniversity of Fukui,
supervised by Prof Koichi Aoki. Then she worked as a Senior
Researcher at MAEDAKOSEN Company Limited; as a Full-Time
Lecturer at Faculty of Science in Kanazawa University; as a Vis-
iting Scholar at Henry White's laboratory in University of Utah. In
2001, she moved to University of Fukui and worked as an As-
sociate Professor and was appointed as a Full Professor at De-
partment of Applied Physics in 2017. She has set the life aiming
to solving fundamental subjects of basic electrochemistry and
defined the work focus into physics of interfacial phenomena.
During her career, over the past 17 years, she has supervised
more than 30 PhD students. She has published more than 90
papers in reputed journals.
jchen@u-fukui.ac.jpA concept of double layer capacitance
motivated by nanotechnology
Jingyuan Chen
1
and Koichi Jeremiah Aoki
2
1
University of Fukui, Japan
2
Electrochemistry Museum, Takagichuoh 3-1304, Fukui, 910-0806,
Japan
Jingyuan Chen, Nano Res Appl Volume:4
DOI: 10.21767/2471-9838-C6-024