Achieving simultaneous enhancement of activity and stability in acidic oxygen evolution through Yb and La Co-doping-induced reaction pathway switch on RuO2 catalysts

The development of anode catalysts with high activity and stability is crucial for advancing proton exchange membrane water electrolysis (PEMWE). RuO 2 is a promising, cost-effective alternative to IrO 2 for the acidic oxygen evolution reaction (OER); however, its practical deployment is critically limited by ruthenium site dissolution and irreversible lattice oxygen loss. To address these challenges, a “rare-earth co-doping, electronic structure modulation, and reaction pathway steering” strategy was developed and successfully applied to synthesize Yb- and La-co-doped RuO 2 nanosheets (Yb,La-RuO 2 ) via a salt-templating method. The resulting catalyst exhibits outstanding OER performance in 0.1 M HClO 4 , delivering a low overpotential of 205 mV at 10 mA cm −2 and maintaining stable operation for 500 h. When employed as the anode catalyst in a PEMWE, it maintains stable operation at a current density of 500 mA cm −2 for 200 h. Density functional theory (DFT) and X-ray absorption spectroscopy reveal that La primarily serves as an electron donor to optimize the intrinsic activity of Ru sites, whereas Yb strengthens lattice oxygen bonding, thereby enhancing structural robustness. Their synergistic interaction modulates the electronic structure of Ru and reduces the covalency of Ru–O bonds. Furthermore, in situ attenuated total reflection–surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) analysis demonstrates that Yb and La co-doping shifts the reaction mechanism from the lattice oxygen mechanism (LOM)—a pathway prone to oxidative degradation—toward the more stable adsorbate evolution mechanism (AEM). This transition effectively suppresses Ru overoxidation and dissolution, significantly improving catalyst durability. This work presents a rational co-doping approach for designing highly efficient and acid-stable OER catalysts, offering valuable insights for the practical deployment of PEMWE technology.