Estimation of exchange current density for hydrogen evolution reaction of copper electrode by using the differentiating polarization method

Wide application of the Tafel extrapolation method (TEM) for the estimation value of the exchange current density (i(0)) on the hydrogen evolution reaction (HER) is still hindered because of some issues. For example, a possibility of improper reading of the tafel slope and the physical resistant such as an oxide film on electrode and solution resistance which requires more consideration in the calculation. The differential polarization method (DPM) was introduced as a reliable method to estimate the value of the is. In this paper, HER of a copper electrode in 0.5 mol dm(-3) H2SO4 solution was investigated and compared using both methods. The DPM shows that the undesirable physical factor of copper in the measurement could be removed rationally and is acceptable on the calculation of is. Moreover, the tafel slope region could be read accurately.