A nichrome rod with 4 mm diameter (0.126 cm2) and a known length was sealed in a plastic tube of matching length. One end was used as the electrode connection held out of the plastic tube, the other as the working electrode surface. The surface was polished with alumina slurry (0.05 m), washed with 1:1 nitric acid, absolute ethanol and double distilled deionized water in an ultrasonic bath subsequently and allowed to dry in the air.