Huang Jun, Li Chen-Kun
Institute of Energy and Climate Research, Theory and Computation of Energy Materials (IEK-13), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
College of Chemistry and Chemical Engineering, Central South University, 410083 Changsha, People's Republic of China.
J Phys Condens Matter. 2021 Apr 20;33(16). doi: 10.1088/1361-648X/abef9d.
Physical modeling helps to acquire fundamental insights from experimental data when electrochemical impedance spectroscopy is employed for mechanistic understandings of electrocatalytic reactions. Herein, we report an analytical model for chemisorption impedance with a consistent treatment of ion transport in the solution and electron transfer on the electrode surface. Our formulation avoids bothdecoupling of double-layer charging and electron transfer reaction, and a strict separation of double-layer charging and ion transport. Ion transport in the entire solution region is described by the Poisson-Nernst-Planck theory and electron transfer kinetics on the electrode surface by the Frumkin-Butler-Volmer theory. Surface dipoles caused by partially charged chemisorbates are considered. The classical Frumkin-Melik-Gaikazyan model for chemisorption is retrieved as a limiting case. The obtained formula is validated using experimental data of hydrogen adsorption at Pt(111). Characteristic frequencies and asymptotic behaviors of chemisorption impedance are analyzed.
当采用电化学阻抗谱来对电催化反应进行机理理解时，物理建模有助于从实验数据中获得基本见解。在此，我们报告了一种化学吸附阻抗分析模型，该模型对溶液中的离子传输和电极表面的电子转移进行了一致处理。我们的公式避免了双层充电与电子转移反应的解耦，以及双层充电与离子传输的严格分离。整个溶液区域的离子传输由泊松 - 能斯特 - 普朗克理论描述，电极表面的电子转移动力学由弗鲁姆金 - 巴特勒 - 伏默理论描述。考虑了由部分带电化学吸附物引起的表面偶极子。经典的弗鲁姆金 - 梅利克 - 加卡齐扬化学吸附模型作为极限情况被推导出来。使用Pt(111)上氢吸附的实验数据对所得公式进行了验证。分析了化学吸附阻抗的特征频率和渐近行为。
