Chemistry Reference
In-Depth Information
6
2
5
4
3
1
9.1
Scheme of the electrochemical cell described in section 9.2.2,
consisting of (1) PVC plates, (2) rubber-ring fittings, (3) PVC tube,
(4) electrolyte solution, (5) screws to tighten the cell parts and
avoid leaking of electrolyte solution and (6) palladium sheet or
textile electrodes.
the plates (1) with rubber fittings (2), having a hole of a specified diameter.
The distance between the electrodes (6) is determined by the length of the
tube (3) positioned between the plates, which is filled with electrolyte solu-
tion (4). The complete structure is held together with screws (5). The metal
sheets, with a thickness of about 0.25 mm are used to characterise the elec-
trochemical cell consisting of 99.995% pure palladium metal obtained from
Goodfellow (Cambridge, UK). The palladium surface was polished on 1200-
grid emery paper to obtain a fresh surface and then further polished with
Al
2
O
3
polishing powder on polishing cloth; to smooth the surface, Al
2
O
3
powder of 1.0, 0.3 and 0.05 mm was used consecutively for 5, 10 and 20 min,
respectively. Finally, the surface was subjected to ultrasonic cleaning for 1
min. The textile electrodes comprised stainless-steel fibres. Knitted, woven
and non-woven structures were tested.
9.2.3
Study of the influence of the
electrolyte concentration
For this study, the composition of the electrolyte was limited to sodium chlo-
ride dissolved in de-ionised water in such a way that concentrations of 1 ¥
10
-1
,1¥ 10
-2
,1¥ 10
-3
and 1 ¥ 10
-4
mol l
-1
were obtained. These solutions were
