化学
吉布斯自由能
反应速率常数
动能
热力学
电子转移
离子强度
能斯特方程
离子键合
动力学
分析化学(期刊)
物理化学
电极
离子
水溶液
色谱法
物理
有机化学
量子力学
作者
Bingyu Liu,Er-Fei Zhen,Lulu Zhang,Jun Cai,Jun Huang,Yan‐Xia Chen
标识
DOI:10.1021/acs.analchem.3c02818
摘要
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 Had 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 HClO4 + (0.1 – x) M NaClO4 (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 HClO4 + (1 – x) M NaClO4 (pH ≤ 2) there is a difference of ca. 5× in the rate constants without and with EDL correction. The importance of proper correction of the EDL effects as well as several other important factors on unveiling the intrinsic pH-dependent reaction kinetics are discussed to help converge our analysis of pH effects in electrocatalysis.
科研通智能强力驱动
Strongly Powered by AbleSci AI