A contribution to the kinetics of hydrogen transport through Pd foil electrode during hydrogen extraction under self-discharge and potentiostatic conditions

This paper contributes to the kinetics of hydrogen transport through the Pd foil electrode in 0.1 mol l(-1) NaOH solution during the hydrogen extracti on from the foil electrode under the self-discharge and potentiostatic cond itions by the analysis of open-circuit potential and anodic current transie nts, respectively. The hydrogen oxidation rate calculated based upon the mi xed potential theory just equals the rate of hydrogen self-discharge from t he electrode during the OCP transient. When the electrode surface is subjec ted even to a constant discharging potential, the hydrogen concentration gr adient at the surface is given by the Butler-Volmer equation combined with the decay in actual potential jump with time below the transition dischargi ng potential; however, the constant hydrogen concentration condition is sat isfied at the surface above this potential. By taking the hydrogen oxidatio n rate during the OCP transient and the two constraints during the anodic c urrent transient as the boundary condition at the surface, the hydrogen con centration profile transients have been derived during the hydrogen extract ion under the self-discharge and potentiostatic conditions, respectively.