biostudies-literatureHuang YCNatural Science Foundation of Hunan ProvinceNational Science and Technology Councile2401236https://www.ebi.ac.uk/biostudies/studies/S-EPMC11515896biostudies-literatureUnknown11(40)Anionic redox allows the direct formation of O─O bonds from lattice oxygens and provides higher catalytic in the oxygen evolution reaction (OER) than does the conventional metal ion mechanism. While previous theories have predicted and experiments have suggested the possible O─O bond, it has not yet been directly observed in the OER process. In this study, operando soft X-ray absorption spectroscopy (sXAS) at the O K-edge and the operando Raman spectra is performed on layered double CoFe hydroxides (LDHs) after intercalation with [Cr(C₂O₄)₃]^3-, and revealed a three-step oxidation process, staring from Co²⁺ to Co³⁺, further to Co⁴⁺ (3d6L), and ultimately leading to the formation of O─O bonds and O₂ evoluAdvanced science (Weinheim, Baden-Wurttemberg, Germany)Direct Identification of O─O Bond Formation Through Three-Step Oxidation During Water Splitting by Operando Soft X-ray Absorption Spectroscopy.PMC11515896MoST 110‐2112‐M‐032‐013‐MY3MoST 109‐2124‐M‐009‐002‐MY32020JJ5039MoST 108‐2118‐E‐032‐003‐MY3MoST 110-2112-M-032-013-MY3MoST 109-2124-M-009-002-MY3MoST 108-2118-E-032-003-MY3Chen CLHu ZChou WCDong CLZhang LHuang YCChen JLLu YRWang SChen CTJing CLin HJWang YWu YZhou JfalseDirect Identification of O─O Bond Formation Through Three-Step Oxidation During Water Splitting by Operando Soft X-ray Absorption Spectroscopy.Anionic redox allows the direct formation of O─O bonds from lattice oxygens and provides higher catalytic in the oxygen evolution reaction (OER) than does the conventional metal ion mechanism. While previous theories have predicted and experiments have suggested the possible O─O bond, it has not yet been directly observed in the OER process. In this study, operando soft X-ray absorption spectroscopy (sXAS) at the O K-edge and the operando Raman spectra is performed on layered double CoFe hydroxides (LDHs) after intercalation with [Cr(C₂O₄)₃]^3-, and revealed a three-step oxidation process, staring from Co²⁺ to Co³⁺, further to Co⁴⁺ (3d6L), and ultimately leading to the formation of O─O bonds and O₂ evolu2024-01-01T00:00:00Z2024 Oct2026-07-15T14:43:58.645Z2026-07-06T03:07:49.772ZS-EPMC115158963909083610.1002/advs.202401236