An investigation of the hydrogen absorption reaction into, and the hydrogen evolution reaction from, a Pd foil electrode

The hydrogen absorption reaction (har) into, and the hydrogen evolution reaction (her) from, Pd foil electrode have been investigated in 0.1 M NaOH solution by using electrochemical impedance spectroscopy. The generalised Faradaic admittance for the indirect har into, and her from, metal foil electrodes under the impermeable boundary conditions has been derived on the basis of Lim and Pyun's kinetic approach to har and her. The measured impedance spectra were analysed by using a complex non-linear least squares data-fitting method applied to the derived Faradaic admittance. Also, impedance spectra were theoretically calculated with different kinetic parameters for the har and her having physical significance in order to characterise the influence of each kinetic parameter on the change of the impedance spectra in the Pd foil electrode.