Cr/Ir Dual-Atom-Doped Cr0.2Ir0.1Ru0.7O2 Electrocatalysts for Overcoming the Activity–Stability Trade-Off in Acidic Water Electrolysis

Abstract Developing efficient and stable oxygen evolution reaction (OER) catalysts under acidic conditions for proton exchange membrane water electrolyzers (PEMWE) is still a pivotal challenge owing to the trade-off between activity and stability. Herein, we synthesize a Cr/Ir dual-atom-doped Cr0.2Ir0.1Ru0.7O2 electrocatalyst, which not only presents a low overpotential of 202 mV but also achieves a long-term stability over 1100 h at 10 mA cm–2 in acidic OER. Importantly, the PEMWE device assembled by using Cr0.2Ir0.1Ru0.7O2 as the anode can operate stably over 1300 h at 0.3 A cm–2. Combining operando spectroscopies (Raman, ATR-SEIRAS, and DEMS) and density functional theory, we find that the Cr and Ir dual-atom incorporation efficiently regulates the electronic structure of Ru and enhances the intrinsic activity of Ru sites, while Ir doping shortens the Ru–O bonds to stabilize lattice oxygen, effectively suppressing the lattice-oxygen-mediated mechanism (LOM) and predominantly following the adsorbate evolution mechanism (AEM). This predominant AEM pathway, together with the downshifted d-band center of Ru and optimized *OOH binding, breaks the conventional activity–stability trade-off of the OER electrocatalysts. In short, Cr/Ir dual-atom doping provides a useful synergistic complementary strategy for high-performance PEMWE anode catalysts.