RuO₂-CeO₂ Lattice Matching Strategy Enables Robust Water Oxidation Electrocatalysis in Acidic Media via Two Distinct Oxygen Evolution Mechanisms

The discovery of acid-stable and highly active electrocatalysts for the oxygen evolution reaction (OER) is crucial in the quest for high-performance water-splitting technologies. Herein, a heterostructured RuO2-CeO2 electrocatalyst was constructed by using a lattice-matching strategy. The interfacial Ru-O-Ce bridge structure provided a channel for electron transfer between Ru and Ce, creating a lattice stress that distorts the local structure of RuO2. The resulting RuO2-CeO2 catalyst exhibited attractive stability with negligible decay after 1000 h of the OER in 0.5 M H2SO4, along with high activity with an overpotential of only 180 mV at 10 mA cm(-2). In situ attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS), in situ differential electrochemical mass spectrometry (DEMS), and density functional theory (DFT) calculations were used to reveal that the interface and noninterface RuO2 sites enabled an oxide path mechanism (OPM) and the enhanced adsorbate evolution mechanism (AEM-plus), respectively, during the OER. The simultaneous and independent OER pathways accessible by lattice matching guides improved electrocatalyst design for the OER in acidic media.