Synergistic Ruthenium-Doped Amorphous IrO_<i>x</i> Matrix for Robust Oxygen Evolution

Iridium oxides (IrO_<i>x</i>) are benchmark catalysts for the acidic oxygen evolution reaction, but their performance is often constrained by a trade-off between catalytic activity and long-term stability. Herein, we utilize an amorphous IrO_<i>x</i> matrix as a robust scaffold for synergistic ruthenium (Ru) doping, a strategy designed to enhance catalytic activity while maintaining an exceptional stability. A simple nitrate-assisted synthesis produces ultrathin Ru-doped amorphous IrO_<i>x</i> nanosheets (2.36 nm thick) with a significantly enhanced specific surface area. Combined spectroscopic analysis and density functional theory calculations reveal that atomically dispersed Ru dopants induce charge transfer to adjacent Ir sites, which optimizes the Ir d-band electronic structure. This electronic modulation not only lowers the energy barrier for the rate-determining *O to *OOH transformation but also critically ensures the reaction proceeds via the stable adsorbate evolution mechanism while suppressing the degradative lattice oxygen mechanism. Benefiting from the above advantages, the optimized Ru_0.0738–IrO_<i>x</i> catalyst exhibits excellent catalytic activity, achieving 10 mA cm^–2 at a low overpotential of 225 mV with outstanding stability for over 100 h, far surpassing commercial IrO₂ and RuO₂. This study highlights a synergistic doping strategy within an amorphous matrix to overcome the intrinsic performance limitations of iridium-based oxides for robust oxygen evolution.