Area-Independent Approach for Measuring Electrosorption Kinetics without Assuming Specific Isotherm Models: Application to Hydrogen Underpotential Deposition

Abstract

Despite significant advancements in electrochemical techniques, kinetic measurements in electrocatalysis still predominantly rely on voltammetric curves and Tafel plots, which can lead to data misinterpretation and overestimation of catalytic efficiency due to area effects. Addressing this gap, this article introduces a staircase voltammetry-based method to investigate the kinetics of electrosorption. By leveraging the pulsed nature of staircase voltammetry, this approach enables the determination of rate constants independent of real electrode surface area, using a single voltammetric cycle. The method was applied to study hydrogen underpotential deposition (HUPD) on polycrystalline platinum using electrodes with varying roughness. Thermodynamic and kinetic parameters were determined for the two voltammetric peaks. Furthermore, the underlying theory of the method is thoroughly presented, facilitating its extension to other systems.