Spin-Enhanced O-H Cleavage in Electrochemical Water Oxidation

Qing Huang; Shijie Xie; Jinjie Hao; Zijing Ding; Chuang Zhang; Hua Sheng; Jincai Zhao

doi:10.1002/anie.202300469

Spin-Enhanced O-H Cleavage in Electrochemical Water Oxidation

Angew Chem Int Ed Engl. 2023 May 8;62(20):e202300469. doi: 10.1002/anie.202300469. Epub 2023 Apr 12.

Authors

Qing Huang^{1

2}, Shijie Xie^{1

2}, Jinjie Hao^{1

2}, Zijing Ding³, Chuang Zhang^{1

2}, Hua Sheng^{1

2}, Jincai Zhao^{1

2}

Affiliations

¹ Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences, Institute of Chemistry Chinese Academy of Sciences, Beijing, 100190, P. R. China.
² University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
³ Heifei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, P. R. China.

PMID: 36932854
DOI: 10.1002/anie.202300469

Abstract

Herein we report the vital role of spin polarization in proton-transfer-mediated water oxidation over a magnetized catalyst. During the electrochemical oxygen evolution reaction (OER) over ferrimagnetic Fe₃ O₄ , the external magnetic field induced a remarkable increase in the OER current, however, this increment achieved in weakly alkaline pH (pH 9) was almost 20 times that under strongly alkaline conditions (pH 14). The results of the surface modification experiment and H/D kinetic isotope effect investigation confirm that, at weakly alkaline pH, during the nucleophilic attack of Fe^IV =O by molecular water, the magnetized Fe₃ O₄ catalyst polarizes the spin states of the nucleophilic attacking intermediates. The spin-enhanced singlet O-H cleavage and triplet O-O bonding occur synergistically, which promotes the O₂ generation more significantly than the strongly alkaline case involving only spin-enhanced O-O bonding.

Keywords: Electrochemistry; Magnetic Field; O−H Cleavage; Spin Polarization; Water Splitting.

Abstract

Grants and funding