Question

(i) Plot the current density vs. overvoltage (j vs. h) relationship – the Butler-Volmer equation – for
this reaction in the range h = -0.5 to 0.5 V. Assume a transfer coefficient a = 0.5 and vary the
exchange current density: j0 = 10-3, 10-6, 10-9 A/cm2. Define the sign conventions for current and
overvoltage.
(ii) Plot the j vs. h relationship for j0 = 10-6 A/cm2 and a = 0.25, 0.5 and 0.75.
(iii) Plot log½j½ vs. h curves under the same approximation for j0 = 10-6 A/cm2, a = 0.5, and compare
with the corresponding Tafel approximation.

Answer 1