IrRuO_x/TiO₂ a stable electrocatalyst for the oxygen evolution reaction in acidic media

Proton Exchange Membrane Electrolysis of Water (PEMWE) stands out as a scalable, CO₂-free process to produce H₂ for energy delivery and industrial applications. Due to the limited Ir and Ru worldwide availability, one of the main challenges for the GW-scale PEMWE implementation is the loading reduction of these metals in the anodic catalytic layer. Here, Ir–Ru loading (5 wt%Ir-40 wt%Ru) was deposited through their impregnation over TiO₂, followed by a thermal-oxidative treatment, obtaining IrRuO_x/TiO₂ catalyst. SEM-EDS and HR-TEM confirmed the homogeneous dispersion of IrRuO_x on TiO₂. The supported catalyst showed a 1.4-fold higher mass activity (85 mA/mg Ir–Ru) for the oxygen evolution reaction (OER) than a mechanical mixture of IrO₂–RuO₂ 1:3 (54 mA/mg_Ir+Ru) in H₂SO₄ 0.5 M, at 1.52 V/RHE. Furthermore, the supported catalyst retains 90% of its catalytic activity after 100 reaction cycles suggesting the RuO₂ intermediate species stabilization by IrO_x, which can avoid its irreversibly transform into hydrous RuO_x.