Chemistry Reference
In-Depth Information
160
000
3
140
000
3
120
000
100
000
80
000
60
000
40
000
2
20
000
3
0
0
50
000
100
000
150
000
200
000
250
000
300
000
(a)
Z
r
16
000
2
14
000
12
000
10
000
8000
2
6000
4000
2000
1
2
1
0
0
5000
10
000
15
000
20
000
25
000
30
000
(b)
Z
r
9.8
Nyquist plots recorded at an electrochemical cell with palladium
electrodes or woven, non-woven or knitted textile electrodes with
A
=
180 mm
2
and
d
=
103 mm for a NaCl concentration of (1) 1
¥
10
-
2
,
(2) 1
¥
10
-
3
and (3) 1
¥
10
-
4
mol l
-
1
at T
=
298.0 K. Part b is an
enlargement of part a.
cells were measured as a function of frequency in the range of 0.1-1 MHz
with
A
= 180 mm
2
and
d
= 103 mm. Some curves are shown in Fig. 9.8 and Fig.
9.9. It can be seen that the Nyquist plot corresponding to the textile elec-
trodes is almost identical to those obtained for the palladium electrodes.
Well-shaped semi-circles are obtained, and a value for
Z
r
without phase-
angle shift can be determined clearly at the completion of the semi-circle.
In principle, it is possible to take account of the different values of the elec-
trolyte resistance obtained in this section and those obtained in section 9.1
because
d
is different. This can be done using Equation 9.5, but at this stage
of the study it is not known whether the behaviour of the textile electrodes
