Chemistry Reference
In-Depth Information
9.2. For this purpose, the starting situation in this section is reflected by
Equation 9.1 and, depending on the results obtained, will show whether this
equation is still valid and, if so, under which conditions. Possible differences
in results between those described in this section and those in section 9.2
need to be explained by the fact that a textile structure is used as electrode
material, since this is the only modification of the electrochemical cell char-
acterised in section 9.2 and used for the studies described here in section
9.3.
In this investigation, a set of two identical electrodes (same material, type
of textile structure and geometrical surface area) will always be used. In
principle, it can be interesting to vary these parameters and to use two dif-
ferent electrodes in the electrochemical cell in order to gain information
about the properties of one single electrode (e.g. by using an electrode with
a small surface area and another with a large surface area). As will be seen
further in this work, this approach will have both advantages and disad-
vantages; where appropriate, its advantages will be exploited in order to
derive further insight into the behaviour, although this will not be the stan-
dard procedure. Therefore, preference is given to the study of textile elec-
trodes in electrochemical cells with identical electrodes.
9.3.2 Characterisation of the electrochemical cell with
textile electrodes
Introduction
Similar to the experiments carried out at palladium electrodes and
described in Chapter 3, the concentration of electrolyte (
c
), the electrode
surface area (
A
) and the distance between the electrodes (
d
) will be
studied as a function of type of textile structure. In this work, three
structures will be studied: knitted, woven and non-woven textile structures,
all obtained from stainless-steel fibres. To complete the data of this work,
palladium sheets will also be inserted in the study as a fourth set of
electrodes. Therefore, for palladium electrodes, the work described in
section 9.2 will actually be repeated here in order to have a direct com-
parison between results obtained with palladium electrodes and textile
electrodes. Of course, correlation with the data obtained in section 9.2 will
be verified.
Electrolyte concentration study
A first parameter to be investigated is the concentration of the NaCl solu-
tion. Electrochemical cells with electrolyte concentrations of 1 ¥ 10
-1
,1¥
10
-2
,1¥ 10
-3
and 1 ¥ 10
-4
mol l
-1
NaCl were prepared. Impedances at these
