The electrocatalytic production of hydrogen (H2), a clean fuel with high energy densit, from water splitting has been considered a promising approach for advancing sustainable energy systems. Compared to the hydrogen evolution reaction (HER) at the cathode, the oxygen evolution reaction (OER) at the anode in a water electrolyzer requires much higher overpotentials due to its sluggish kinetics of the complex four-electron transfer process. Moreover, for acidic OER, the use of a large amount of iridium oxide (IrO2) at the anode is a major obstacle for the large-scale commercialization of water electrolysis In this work, we present a facile synthetic approach to fabricate IrCoOx electrocatalysts to improve the dispersion of IrOx and reducing the overall cost of hydrogen production. In situ characterization shows that the structure containing two atomic layers of IrOx is highly ordered and stable under OER conditions, while the conventional IrOx clusters undergo structural reconstruction. Density functional theory (DFT) calculations indicate that compared to the conventional IrOx clusters, the stronger interaction between the two atomic layers of IrOx and CoOx optimizes the binding energies of key OER intermediates. The facile sample preparation method offers the opportunity for the scale-up fabrication of active, stable, and lower-cost IrCoOx OER electrocatalysts for practical applications.
