Chemistry Reference
In-Depth Information
5.4
4.9
Palladium
y
= -0.9937x + 1.4972
R
2
= 0.9999
4.4
Woven
y
= -0.9942x + 1.502
R
2
= 0.9999
3.9
Knitted
y
= -0.9938x + 1.4914
R
2
= 0.9999
3.4
Non-woven
y
= -0.994x + 1.4963
R
2
= 0.9999
2.9
2.4
-4.0
-3.5
-3.0
-2.5
-2.0
-1.5
-1.0
Log
c
(mol l
-1
)
9.10
Logarithmic plot of the impedance at zero phase-angle shift as a
function of electrolyte concentration obtained from the
electrochemical cell with palladium electrodes, woven, knitted
and non-woven electrodes for
A
=
180 mm
2
,
d
=
103 mm and
T
=
298.0 K.
Ta b le 9.4
Impedance data in ohm for the calibration curves shown in Fig. 9.10
c
(mol l
-
1
)
lectrode type
Palladium
Woven
Knitted
Non-woven
10
-
1
312
±
2
316
±
2
308
±
2
311
±
7
10
-
2
3 073
±
70
3113
±
79
3030
±
78
3 060
±
205
10
-
3
29 000
±
700
29 400
±
700
28 700
±
800
29 100
±
1900
10
-
4
303 000
±
5000
308 000
±
6000
299 000
±
6000
303 000
±
13 000
with the calibration curve obtained at palladium electrodes. From Table 9.4,
the shift becomes clear when comparing impedances obtained at different
types of electrodes. The experiments undertaken to obtain the data in Fig.
9.10 were repeated several times, and the same observation could always
be made in a reproducible way.
In order to explain the two remarks described above, it is necessary to
look at the structure of the textile electrodes and compare them with the
flat palladium sheet electrodes. The measured impedance is in fact an
average of a very large number of individual impedances at different
