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Antiferromagnetic Inverse Spinel Oxide LiCoVO 4 with Spin‐Polarized Channels for Water Oxidation
Author(s) -
Chen Riccardo Ruixi,
Sun Yuanmiao,
Ong Samuel Jun Hoong,
Xi Shibo,
Du Yonghua,
Liu Chuntai,
Lev Ovadia,
Xu Zhichuan J.
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201907976
Subject(s) - antiferromagnetism , materials science , spinel , magnetic moment , oxygen evolution , oxide , spin states , magnetism , chemical physics , condensed matter physics , inorganic chemistry , chemistry , physics , electrochemistry , electrode , metallurgy
Exploring highly efficient catalysts for the oxygen evolution reaction (OER) is essential for water electrolysis. Cost‐effective transition‐metal oxides with reasonable activity are raising attention. Recently, OER reactants' and products' differing spin configurations have been thought to cause slow reaction kinetics. Catalysts with magnetically polarized channels could selectively remove electrons with opposite magnetic moment and conserve overall spin during OER, enhancing triplet state oxygen molecule evolution. Herein, antiferromagnetic inverse spinel oxide LiCoVO 4 is found to contain d 7 Co 2+ ions that can be stabilized under active octahedral sites, possessing high spin states S = 3/2 ( t 2g 5 e g 2 ). With high spin configuration, each Co 2+ ion has an ideal magnetic moment of 3 µ B , allowing the edge‐shared Co 2+ octahedra in spinel to be magnetically polarized. Density functional theory simulation results show that the layered antiferromagnetic LiCoVO 4 studied contains magnetically polarized channels. The average magnetic moment ( µ ave ) per transition‐metal atom in the spin conduction channel is around 2.66 µ B . Such channels are able to enhance the selective removal of spin‐oriented electrons from the reactants during the OER, which facilitates the accumulation of appropriate magnetic moments for triplet oxygen molecule evolution. In addition, the LiCoVO 4 reported has been identified as an oxide catalyst with excellent OER activity.