The pH-Induced Increase of the Rate Constant for HER at Au(111) in Acid Revealed by Combining Experiments and Kinetic Simulation

作者：Bingyu Liu, Er-Fei Zhen, Lulu Zhang, Jun Cai, Jun Huang, Yanxia Chen · 发表于：Analytical Chemistry · 年份：2023 · DOI：10.1021/acs.analchem.3c02818 · 被引用次数：14 · 研究领域：Electrocatalysts for Energy Conversion、Electrochemical Analysis and Applications、Advanced battery technologies research

Origins of pH effects on the kinetics of electrocatalytic reactions involving the transfer of both protons and electrons, including the hydrogen evolution reaction (HER) considered in this study, are heatedly debated. By taking the HER at Au(111) in acid solutions of different pHs and ionic concentrations as the model systems, herein, we report how to derive the intrinsic kinetic parameters of such reactions and their pH dependence through the measurement of j–E curves and the corresponding kinetic simulation based on the Frumkin–Butler–Volmer theory and the modified Poisson–Nernst–Planck equation. Our study reveals the following: (i) the same set of kinetic parameters, such as the standard activation Gibbs free energy, charge transfer coefficient, and Gibbs adsorption energy for H ad at Au(111), can simulate well all the j–E curves measured in solutions with different pH and temperatures; (ii) on the reversible hydrogen electrode scale, the intrinsic rate constant increases with the increase of pH, which is in contrast with the decrease of the HER current with the increase of pH; and (iii) the ratio of the rate constants for HER at Au(111) in x M HClO 4 + (0.1 – x ) M NaClO 4 (pH ≤ 3) deduced before properly correcting the electric double layer (EDL) effects to the ones estimated with EDL correction is in the range of ca. 10 to 40, and even in a solution of x M HClO 4 + (1 – x ) M NaClO 4 (pH ≤ 2) there is a difference of ca. 5× in the rate constants without and with EDL cor...