Direct Identification of O─O Bond Formation Through Three-Step Oxidation During Water Splitting by Operando Soft X-ray Absorption Spectroscopy

Yu Cheng Huang, Yujie Wu, Ying Rui Lu, Jeng Lung Chen, Hong Ji Lin, Chien Te Chen, Chi Liang Chen, Chao Jing, Jing Zhou, Linjuan Zhang, Yanyong Wang, Wu Ching Chou*, Shuangyin Wang*, Zhiwei Hu*, Chung Li Dong*

*此作品的通信作者

研究成果: Article同行評審

1 引文 斯高帕斯(Scopus)

摘要

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 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.

原文English
文章編號2401236
期刊Advanced Science
11
發行號40
DOIs
出版狀態Published - 28 10月 2024

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