Year: 2026
Type: article
Abstract: The hydrogen evolution reaction is central to electrochemistry, yet the distinct activity trends separating d-block from s/p-block metals have long eluded a unified mechanistic explanation. Here, we re-evaluate the relationship between exchange current density (log j0) and work function (Φ) using the average data for polycrystalline surfaces, revealing that Groups 4−10 and s/p-block metals collapse onto a single linear correlation, while Group 11−12 metals follow a parallel trend offset by ≈2.15 log units. We propose a unified kinetic framework incorporating two descriptors: work function, which lowers the electron-transfer barrier, and valence electronic configuration, which governs H−H coupling. Metal atoms with at least two exposed half-filled orbitals (Groups 4−10, s/p-block) facilitate direct on-surface coupling. In contrast, Group 11−12 metal atoms, lacking sufficient half-filled orbitals, force a diffusion-mediated pathway, incurring a thermodynamic penalty. By deriving rate equations that explicitly include these material properties, this work may resolve historical ambiguities and offer a quantitative, predictive criterion for the rational design of high-performance electrocatalysts.
Source: ACS electrochemistry.
Author: Youyi Sun
Language: English
Field: Energy
Domain: Physical Sciences
Open Access status: bronze
Funder: China Scholarship Council
OpenAlex ID: W7166582960