One-dimensional gold-doped monoclinic iridium oxide nanoribbons for high-efficiency acidic oxygen evolution reaction

Abstract

Proton exchange membrane water electrolysis (PEMWE) stands as the predominant technique for the production of high-purity hydrogen. However, it is confronted with a significant impediment due to the sluggish kinetics inherent to the anodic oxygen evolution reaction (OER). This limitation has spurred the search for catalysts that exhibit both high activity and durability in facilitating the OER. One-dimensional (1D) metastable-phase iridium oxide (IrO₂) has emerged as a promising OER catalyst, yet its catalytic activity and stability have hitherto fallen short of the stringent requirements for industrial-scale applications. Here, by leveraging a heteroatom doping strategy, we have successfully synthesized 1D gold-doped IrO₂ monoclinic nanoribbons (Au-doped IrO₂NRs), further optimizing the electrochemical activity and durability of IrO₂ nanoribbons under acidic conditions. Au-doped IrO₂NRs not only preserve the crystal structure characteristic of monoclinic IrO₂NRs, but also exhibit improved catalytic performance. Under an acidic environment, Au-doped IrO₂NRs reach a low overpotential of 180 mV at a current density of 10 mA cm⁻², a low Tafel slope of 40.6 mV dec⁻¹, and a durable stability of 160 h at 10 mA cm⁻². When integrating into the anode compartment of a practical PEMWE system, Au-doped IrO₂NRs sustained operation for more than 500 h at 60 °C. These results highlight the capacity of Au-doped IrO₂NRs to promote the performance and endurance of PEMWE, which in turn supports the wider implementation of hydrogen as a sustainable energy carrier.