Supramolecular Engineering of Vinylene‐Linked Covalent Organic Framework – Ruthenium Oxide Hybrids for Highly Active Proton Exchange Membrane Water Electrolysis

Abstract

The controlled formation of a functional adlayer at the catalyst‐water interface is a highly challenging yet potentially powerful strategy to accelerate proton transfer and deprotonation for ultimately improving the performance of proton‐exchange membrane water electrolysis (PEMWE). In this study, the synthesis of robust vinylene‐linked covalent organic frameworks (COFs) possessing high proton conductivities is reported, which are subsequently hybridized with ruthenium dioxide yielding high‐performance anodic catalysts for the acidic oxygen evolution reaction (OER). In situ spectroscopic measurements corroborated by theoretical calculations reveal that the assembled hydrogen bonds formed between COFs and adsorbed oxo‐intermediates effectively orient interfacial water molecules, stabilizing the transition states for intermediate formation of OER. This determines a decrease in the energy barriers of proton transfer and deprotonation, resulting in exceptional acidic OER performance. When integrated into a PEMWE device, the system achieves a record current density of 1.0 A cm⁻² at only 1.54 V cell voltage, with a long‐term stability exceeding 180 h at industrial‐level 200 mA cm⁻². The approach relying on the self‐assembly of an oriented hydrogen‐bonded adlayer highlights the disruptive potential of COFs with customizable structures and multifunctional sites for advancing PEMWE technologies.