Dodecylamine-Assisted Hydrothermal Synthesis of Carbon-Supported Ultrafine IrRu Nanoparticles for Oxygen Evolution Electrocatalysis and Overall Water Splitting

Abstract

Ruthenium (Ru)- and iridium (Ir)-based nanomaterials have always been regarded as efficient electrocatalysts for oxygen evolution reaction (OER) in acidic electrolytes. Herein, we develop a facile dodecylamine-assisted hydrothermal synthesis for producing carbon-supported IrRu alloy nanoparticles with controllable Ir/Ru ratios and ultrafine sizes towards high-efficiency OER and overall water electrolysis. In this strategy, the dodecylamine that serves as a capping and reducing agent enables the final IrRu alloy nanoparticles to possess average sizes <3 nm and high degree of dispersion on carbon substrate. By combining high OER activity of Ru with high acidic robustness of Ir, the as-prepared IrRu/C nanoparticles at a suitable Ir/Ru ratio of 1/3 show good activity and durability for the OER electrocatalysis and overall water splitting. In specific, the Ir₁Ru₃/C catalyst exhibits the lowest overpotential of 302 mV at the current density of 10 mA cm⁻² and the highest mass activity of 120.5 mA mg⁻¹ at 1.532 V for OER in 0.5 M H₂SO₄ electrolyte. In addition, a two-electrode acidic electrolyzer assembled with Ir₁Ru₃/C at anode and commercial Pt/C at cathode (Pt/C|| Ir₁Ru₃/C) exhibits a low cell voltage of 1.44 V for achieving the current density of 10 mA cm⁻², along with a satisfied 20h durability.