Chemistry Reference
In-Depth Information
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(a)
(b)
(c)
9.12
Scheme showing the positioning of a palladium electrode (a) and
a woven (b) and knitted (c) textile electrode in the cell, and the
influence on the configuration of the electrodes due to
positioning. (1) Rubber fittings, (2) part of the PVC tubing filled
with electrolyte and (3) electrolyte solution.
the surface of the woven structure lies somewhat deeper in the cell, as is
clearly shown in Fig. 9.12b. In fact with woven electrodes, the actual distance
between the electrodes (
d
¢) is a little larger than the geometrical distance
(
d
) determined by the electrochemical cell geometry. For palladium elec-
trodes
d
and
d
¢ are equal. This effect explains a small shift in the calibra-
tion curves to somewhat higher values; in fact a shift of about 1% is
observed, which means that
d
¢ is approximately 1% bigger than
d
.From this
conclusion, it is possible to obtain
d
¢, which is about 104 mm, or for each
woven electrode in the electrochemical cell, the real virtually smoothened
surface of the electrode lies about 0.5 mm deeper compared with the flat
palladium electrodes.
For the knitted structure, the opposite effect is observed. Because of its
elastic structure, the knitted electrode will adapt to the shape of the holders
and fittings used in the electrochemical cell. At the surface of the knitted
