Differentiating approach to the Tafel slope of hydrogen evolution reaction on nickel electrode

•A new technique to assist the Tafel extrapolation method is proposed.•The technique has advantages: (a) accurate reading of the proper Tafel slope region and (b) easy removing of the physical resistances such as oxide film and solution resistance.•The hydrogen evolution reaction on nickel electrode in 0.5 mol dm− 3 H2SO4 solution has j0 = 10-2.3 mA cm− 2 and αc = 0.39.

A new technique was introduced to assist the Tafel extrapolation method (TEM). The hydrogen evolution reaction (her) on nickel electrode in H2SO4 solution was investigated in comparison with the TEM and proposed technique. The exchange current density (j0) for her was assessed from points of simple and more accurate handling. The proposed technique has advantages: (1) proper reading of the Tafel slope region and (2) easy removing of undesirable physical factors such as oxide film and solution resistances.

Graphical abstractLeft hand side: the traditional Tafel estimation using η = a + b log ∣ j ∣.Right hand side: the newly-proposed estimation using dloghexpj−0.003dlogj=−1 ⋂ (8 mA cm− 2 ≤ | j | ≤ 18 mA cm− 2).Download high-res image (297KB)Download full-size image