Direct Identification of OâO Bond Formation Through Three-Step Oxidation During Water Splitting by Operando Soft X-ray Absorption Spectroscopy.
Adv Sci (Weinh)
; : e2401236, 2024 Aug 01.
Article
de En
| MEDLINE
| ID: mdl-39090836
ABSTRACT
Anionic redox allows the direct formation of OâO 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 OâO 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 OâO bonds and O2 evolution above a threshold voltage (1.4 V). In contrast, a gradual oxidation of Fe is observed in CoFe LDHs. The OER activity exhibits a significant enhancement, with the overpotential decreasing from 300 to 248 mV at 10 mA cm-2, following the intercalation of [Cr(C2O4)3]3- into CoFe LDHs, underscoring a crucial role of anionic redox in facilitating water splitting.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Langue:
En
Journal:
Adv Sci (Weinh)
Année:
2024
Type de document:
Article
Pays d'affiliation:
Taïwan
Pays de publication:
Allemagne