Suppressing migration of Ru in a high-entropy alloy for durable acidic oxygen evolution†

Ru-based catalysts are recognized as some of the most advanced materials for acidic oxygen evolution reaction (OER). Nonetheless, their vulnerability to over-oxidation to soluble RuO₄ during catalytic processes presents considerable challenges for their long-term stability. To address the issue of Ru atom leaching within the lattice, a Ru-based high entropy alloy electrocatalyst (HEA/PANI-CP) has been synthesized on polyaniline-modified carbon paper utilizing an innovative “thermal shock” technique. This method employs compositional engineering to amplify the high entropy effects, thereby effectively suppressing element diffusion and controlling the migration energies of active Ru sites. Consequently, the catalyst demonstrates a significant decrease in elemental dissolution, which contributes to enhanced stability during the OER. Importantly, the HEA catalyst exhibits remarkable performance, achieving an overpotential of 258 mV at a current density of 10 mA cm⁻² while exhibiting extraordinary stability with minimal degradation over 300 hours of operation. These results position HEA/PANI-CP as a leading candidate for acid-stable OER catalysts, offering a promising avenue for the advancement of durable Ru-based electrocatalysts.