Graphene-Supported La-Doped RuO ₂ Nanoparticle Electrocatalyst for Acidic Oxygen Evolution

Ruthenium-based materials have become highly promising anode catalysts in proton-exchange membrane electrolyzers. Their durability is compromised under acidic conditions due to dissolution and overoxidation. In this study, we present a La-RuO 2 /G catalyst, achieved by successfully doping lanthanum into the lattice of RuO 2 supported on graphene. This catalyst shows remarkable performance, achieving an overpotential of 186 mV at 10 mA cm –2, with a high mass activity of 678 A g Ru –1 at 1.5 V, which is approximately 36 times and 92 times higher than those of commercial RuO 2 and commercial IrO 2, while maintaining stability for over 120 h. Structural characterization and electrochemical assessments reveal that La doping promotes the favorable electronic redistribution at the Ru site and enhances the oxygen intermediate adsorption and desorption efficiency. Additionally, the transfer of electrons from La to Ru increases the electron density around Ru, mitigating overoxidation and enhancing both activity and stability. Besides, graphene serves as an effective support, not only aiding in electronic conduction but also enhancing the surface area, thereby exposing more active sites. This research outlines a method to adjust the electronic structure of RuO 2 -based oxygen evolution reaction electrocatalysts under acidic conditions, enhancing both their activity and durability.