Spin state and covalent effect in LaCoO3: An17O NMR study

Itoh, Masatoshi; Mori, Masami; Yamauchi, Touru; Ueda, Yutaka

doi:10.1007/bf02571070

Cited by 3 publications

(2 citation statements)

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“…The pDOS for LaCoO 3 evidence the overlap between Co (t 2g ) and O (p) states below Fermi level. The states on E F for 10 at% Fe substituted LaCoO 3 are intermixed Co (e g ) – O(p) states. , The strong hybridization between Co 3d states of e g symmetry and oxygen 2p states leads to formation of broad σ* bands, which cross over the E F . This validates the half-metallic features of LaCo 0.9 Fe 0.1 O 3 .…”

Section: Resultsmentioning

confidence: 99%

“…A gap between minority spin t 2g states forms by the intersection of E F (inset in Figure 7b), which indicates the half metallic feature of La-Co 0.9 Fe 0.1 O 3 . 32 34,35 The strong hybridization between Co 3d states of e g symmetry and oxygen 2p states leads to formation of broad σ* bands, which cross over the E F . 33 This validates the half-metallic features of LaCo 0.9 Fe 0.1 O 3 .…”

Section: Chemistry Of Materialsmentioning

confidence: 99%

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Tailoring the Co 3d-O 2p Covalency in LaCoO₃ by Fe Substitution To Promote Oxygen Evolution Reaction

Duan¹,

Sun²,

et al. 2017

Chem. Mater.

306

232

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LaCoO 3 is an active, stable catalyst in alkaline solution for oxygen evolution reaction (OER). With lower cost, it is a potential alternative to precious metal oxides like IrO 2 and RuO 2 in water electrolysis. However, room still remains for improving its activity according to recent understandings of OER on perovskite oxides. In this work, Fe substitution has been introduced in LaCoO 3 to boost its OER performance. Density function theory (DFT) calculation verified that the enhanced performance originates from the enhanced Co 3d-O 2p covalency with 10 at% Fe substitution in LaCoO 3 . Both DFT calculations and Superconducting Quantum Design (SQUID) magnetometer (MPMS-XL) showed a Co 3+ spin state transition from generally low spin state (LS: t 2g 6 e g 0 , S = 0) to a higher spin state with the effect of 10 at% Fe substitution. X-ray absorption near-edge structure (XANES) supports DFT calculations on an insulator to half-metal transition with 10 at% Fe substitution, induced by spin state transition. The half-metallic LaCo 0.9 Fe 0.1 O 3 possesses increased overlap between Co 3d and O 2p states, which results in enhanced covalency and promoted OER performance. This finding enlightens a new way of tuning the metal−oxygen covalency in oxide catalysts for OER.

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Section: Resultsmentioning

confidence: 99%

Section: Chemistry Of Materialsmentioning

confidence: 99%