The development of efficient and stable electrocatalysts for the oxygen evolution reaction (OER) is crucial for advancing the commercialization of proton exchange membrane water electrolyzers (PEMWEs). Here, we report a ternary oxide catalyst, Ir-RuSnOx, in which atomically dispersed Ir substitutes surface Ru sites to construct an Ir─O─Ru atomic interface. The catalyst requires an overpotential of only 165 mV to deliver 10 mA cm- 2 and maintains stable operation for over 350 h at 100 mA cm- 2. When integrated into a PEMWE, Ir-RuSnOx sustains continuous operation at 1 A cm- 2 for 800 h without observable degradation. Combined electrochemical and theoretical studies reveal that Sn acting as a strong electron donor, enhances electron localization at the bridging oxygen (Obri) within the Ir─O─Ru motif. This enables Obri as a proton acceptor, facilitating deprotonation of O─H and OO─H species at Ru sites, thereby forming Obri─H intermediates, lowering the energy barrier of the rate-determining step (RDS), and accelerating OER kinetics. Simultaneously, Sn incorporation increases the electron density of the Ir─O─Ru structure, strengthening its resistance against oxidative degradation. These findings offer a path to achieving both high activity and long-term durability in acidic OER electrocatalysts.
Li et al. (Thu,) studied this question.