Directed Electron Modulation Stabilizes Iridium Oxide Clusters for High-Current-Density Oxygen Evolution

Abstract

The rapid advancement of the green hydrogen industry has driven a surge in demand for devices that operate over a broad range of current density. Despite this, the development of stable iridium-based catalysts for high-current-density applications in oxygen evolution reactions remains a significant challenge. In this study, directed electron modulation (DEM) of iridium oxide clusters on cobalt hydroxide nanosheets is achieved using a cyclic Joule heating strategy in pure water. The strategy achieves a rapid change of environmental energy during electronic modulation through Joule heating, which ensures strong electronic coupling between IrO₂ and Co(OH)₂ without significant changes in initial catalyst nanostructure and cluster size. Directed electron modulation optimizes the reactant adsorption ability of the active center (IrO₂ cluster) and corresponding reaction kinetics are improved, resulting in the catalyst (DEM-IrO₂@Co(OH)₂-NF) showing excellent performance. The DEM-IrO₂@Co(OH)₂-NF exhibits excellent catalytic activity in alkaline electrolytes with only 296 mV overpotential up to 1 A cm⁻² and no significant degradation in 1000 h stability test at 1 A cm⁻². Additionally, the anion exchange membrane electrolyzer using DEM-IrO₂@Co(OH)₂-NF||Pt/C requires only 1.68 V at 1 A cm⁻² and remains stable for 200 h. This work will provide new directions for optimization of active centers.