Probing Acidic OER Mechanisms on Cobalt/Iridium-Based
Electrocatalysts via In Situ Surface-Enhanced Raman
Spectroscopy
HU Ce-jun2, HU Yan-fang1*, XIE Wei3*
1. Hebei Chemical & Pharmaceutical College, Shijiazhuang 050026, China
2. College of Materials Science and Engineering, Fuzhou University, Fuzhou 350108, China
3. College of Chemistry, Nankai University, Tianjin 300071, China
Abstract：The acidic oxygen evolution reaction (OER) is a core process in proton exchange membrane water electrolyzers. However, the highly corrosive environment and complex reaction pathways pose significant challenges for developing efficient catalysts. Understanding the dynamic evolution of catalytically active sites and the reaction mechanism under realistic operating conditions is crucial for designing highly stable acidic OER catalysts. In this work, highly active and stable CoIrOx catalysts were prepared via a displacement method. Electrokinetic studies revealed that during catalyst activation, cobalt leaching generates surface vacancies, which in turn expose iridium sites that are oxidized to the active Ir5+ phase, thereby promoting the reaction. In situ surface-enhanced Raman spectroscopy (SERS) combined with H/D isotope experiments confirmed that OOH is the key intermediate species in the acidic OER process. Furthermore, 18O isotope labeling was used to probe the dynamic changes in the catalyst's surface microstructure. A pronounced blue shift in the Ir—O vibrational peak at OER potentials indicated that the OER on CoIrOx follows a lattice oxygen oxidation mechanism (LOM). This work provides new insights into the reaction mechanisms of CoIr-based catalysts and offers a novel approach for exploring OER pathways.
胡策军，胡艳芳，谢 微. 钴铱基电催化剂酸性析氧反应的原位表面增强拉曼光谱研究[J]. 光谱学与光谱分析, 2025, 45(11): 3174-3181.
HU Ce-jun, HU Yan-fang, XIE Wei. Probing Acidic OER Mechanisms on Cobalt/Iridium-Based
Electrocatalysts via In Situ Surface-Enhanced Raman
Spectroscopy. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(11): 3174-3181.
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