Regulation of the Dual-Site Mechanism on Transition Metal-Doped RuO2 Catalysts for Direct Electrolysis of Seawater

Abstract

Although direct seawater electrolysis for hydrogen production offers a promising pathway for sustainable energy conversion, it is severely hampered by the anodic competition between the oxygen evolution reaction (OER) and the chlorine oxidation reaction, along with the activity–stability trade-off of catalysts. Herein, we systematically investigated 25 transition metal-doped RuO2 (110) catalysts and considered four reaction mechanisms using density functional theory calculations combined with machine learning (ML) to elucidate their intrinsic activity and selectivity. Comparative thermodynamic analysis identified the oxide pathway mechanism (OPM) as a favorable dual-site route supported by the *OH coverage-dependent surface phase diagrams and lower thermodynamic limiting energies. Based on this thermodynamically favorable OPM framework, eight catalysts were first identified from the initial OER activity screening, and seven of them were finally recommended after further selectivity evaluation against chlorine-related oxidation reactions, among which Ti-RuO2 and Co-RuO2 exhibit the lowest overpotentials of 0.05 and 0.06 V (vs RHE), respectively. Furthermore, ML algorithms were employed to establish a quantitative formula correlating intrinsic electronic structures integrating atomic charges and the integrated crystal orbital Hamilton population with intermediate adsorption energies, thereby revealing the electronic origin of the enhanced activity. This work not only screens high-performance catalysts but also provides a theoretical framework for the rational design of catalysts by breaking linear scaling relations.