EXPERIMENTAL
Instrumentation
The experiments were performed in a standard three electrode configuration in
an electrolytic cell in which carbon fibre, platinum and Ag/AgCl/KCl,,, electrodes
were used as working, counter and reference electrodes respectively. The cell was
used in conjunction with an EG&G PAR Model 273 potentiostat/galvanostat
interfaced to an IBM PS/2 Model 30 computer. The software used was the PAR
Model 270 Electrochemical Analysis System. Two voltammetric techniques were
used; namely differential pulse voltammetry (DPV) and cyclic voltammetry (CV)
using a staircase waveform. For DPV, a pulse amplitude of 50 mV and a pulse
width of 50 ms were used for all measurements. For staircase CV, a scan increment
of 10 mV and step time of 0.1 s were used. All electrochemical measurements were
carried out at room temperature.