|
|
The Preparation of the Samples
|
|
-
The
negative electrode: a pure-lead sheet (99.99%);
-
The electrolyte: sulfuric acid solution of 5M
concentration;
-
Oxygen dissolved in the electrolyte was removed by
bubbling argon gas
for more than 2h beforehand;
-
The lead surface was cleaned with acetic acid to
remove the existing
lead oxide layer, and then washed with ethanol;
-
After preparing the surface of the electrode a
small amount of CaSO4 or Bi2(SO4)3
powder was pressed on the surface;
-
A constant force was applied in order to
fix the sulfates on the
surface of the electrode;
-
The Pb plate was placed in
a cell as the working electrode;
-
In order to reduce any oxides on the lead surface
we applied a negative
potential on two steps;
-
First we applied -1400 mV for 10 min and then -1200
mV for 10 min;
|
|