Gisbert-González José M, Rodellar Carlos G, Druce Jody, Ortega Eduardo, Cuenya Beatriz Roldan, Oener Sebastian Z
Department of Interface Science, Fritz-Haber Institute of the Max Planck Society, Berlin 14195, Germany.
J Am Chem Soc. 2025 Feb 12;147(6):5472-5485. doi: 10.1021/jacs.4c18638. Epub 2025 Feb 3.
The hydrogen evolution reaction (HER) is one of the most prominent electrocatalytic reactions of green energy transition. However, the kinetics across materials and electrolyte pH and the impact of hydrogen coverage at high current densities remain poorly understood. Here, we study the HER kinetics over a large set of nanoparticle catalysts in industrially relevant acidic and alkaline membrane electrode assemblies that are only operated with pure water humidified gases. We discover distinct kinetic fingerprints between the iron triad (Fe, Ni, Co), coinage (Au, Cu, Ag), and platinum group metals (Ir, Pt, Pd, Rh). Importantly, the applied bias changes not only the activation energy () but also the pre-exponential factor (). We interpret these changes as entropic changes in the interfacial solvent that differ between acid and base and entropic changes on the surface due to a changing hydrogen coverage. Finally, we observe that anions can induce Butler-Volmer behavior for the coinage metals in acid. Our results provide a new foundation to understand HER kinetics and, more broadly, highlight the pressing need to update common understanding of basic concepts in the field of electrocatalysis.
析氢反应（HER）是绿色能源转型中最突出的电催化反应之一。然而，不同材料和电解质pH值下的动力学以及高电流密度下氢覆盖的影响仍知之甚少。在此，我们研究了大量纳米颗粒催化剂在工业相关的酸性和碱性膜电极组件中的析氢反应动力学，这些组件仅使用纯水加湿气体运行。我们发现铁系元素（Fe、Ni、Co）、硬币金属（Au、Cu、Ag）和铂族金属（Ir、Pt、Pd、Rh）之间存在明显的动力学特征。重要的是，施加的偏压不仅会改变活化能（），还会改变指前因子（）。我们将这些变化解释为酸和碱之间界面溶剂的熵变以及由于氢覆盖变化导致的表面熵变。最后，我们观察到阴离子可以在酸性条件下诱导硬币金属的巴特勒-沃尔默行为。我们的结果为理解析氢反应动力学提供了新的基础，更广泛地说，突出了更新电催化领域基本概念的普遍认识的迫切需求。
