Koutecký-Levich analysis of the hydrogen evolution reaction on commercial Ni 201 and Ni-based alloy in alkaline media

To elucidate the kinetic and mechanistic behavior of pure metals and commercial alloys toward the hydrogen evolution reaction (HER), kinetic studies were performed by deconvoluting the measured current into its kinetic and mass transport components for nickel 201 (99.6 %) and Inconel 625 electrodes. The objective was to compare the intrinsic electrocatalytic performance of these materials for hydrogen production in alkaline media. Linear sweep voltammetry measurements were conducted using a rotating disk electrode (RDE), and the resulting polarization curves were analyzed according to the Koutecký–Levich model (K-L) to extract the purely kinetic current. Tafel analysis of the deconvoluted kinetic currents revealed alloy-dependent mechanistic variations in the HER. At low cathodic overpotentials, prior to significant hydrogen evolution, concurrent Faradaic processes may interfere with the interpretation of polarization curves by introducing cathodic currents unrelated to HER. K-L deconvolution enables meaningful comparison of HER kinetics over a broad overpotential range by isolating the intrinsic kinetic contribution, thereby providing a more reliable assessment of hydrogen evolution on different commercial alloys.