One-pot synthesis of NiFe nanoarrays under an external magnetic field as an efficient oxygen evolution reaction catalyst

Miao, Yujie; Huang, Qiuping; Wen, Dan; Dan, Xie; Huang, Bo; Lin, Dunmin; Xu, Cheng; Zeng, Wen; Xie, Fengyu

doi:10.1039/d2ra07666g

Cited by 2 publications

(2 citation statements)

References 51 publications

(56 reference statements)

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“…Because the lowest energy state of the oxygen molecule is a paramagnetic triplet state, the formation of oxygen from OH − in a diamagnetic singlet state is favored when both adsorbed O molecules have aligned spins. [ 19a,20c,27 ] The higher spin‐polarization of Ni within NiOOH/MnFeOOH compared with Ni within NiOOH can favor a higher degree of parallel spin alignment of the oxygen intermediates. The spin–orbit interactions between Ni and the OER intermediates are shown in Figure 4f.…”

Section: Resultsmentioning

confidence: 99%

“…Thus the kinetics of this reaction strongly depends on the spin state of the catalytic sites. [ 20 ] Inspired by this, several previous works have detailed the tuning of the spin state of the electrocatalyst to facilitate the combination of oxygen atoms with parallel spin arrangement. However, manipulating spins has typically relied on external magnetic fields, [ 21 ] an approach that is impractical for real‐world device applications.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Oxygen Evolution and Zinc‐Air Battery Performance via Electronic Spin Modulation in Heterostructured Catalysts

Yang,

He,

Botifoll

et al. 2024

Advanced Materials

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Beyond optimizing electronic energy levels, the modulation of the electronic spin configuration is an effective strategy, often overlooked, to boost activity and selectivity in a range of catalytic reactions, including the oxygen evolution reaction (OER). This electronic spin modulation is frequently accomplished using external magnetic fields, which makes it impractical for real applications. Herein, spin modulation is achieved by engineering Ni/MnFe2O4 heterojunctions, whose surface is reconstructed into NiOOH/MnFeOOH during the OER. NiOOH/MnFeOOH shows a high spin state of Ni, which regulates the OH‐ and O2 adsorption energy and enables spin alignment of oxygen intermediates. As a result, NiOOH/MnFeOOH electrocatalysts provide excellent OER performance with an overpotential of 261 mV at 10 mA/cm2. Besides, rechargeable zinc‐air batteries based on Ni/MnFe2O4 show a high open circuit potential of 1.56 V and excellent stability for more than 1000 cycles. This outstanding performance is rationalized using density functional theory calculations, which show that the optimal spin state of both Ni active sites and oxygen intermediates facilitates spin‐selected charge transport, optimizes the reaction kinetics, and decreases the energy barrier to the evolution of oxygen. This study provides valuable insight into spin polarization modulation by heterojunctions enabling the design of next‐generation OER catalysts with boosted performance.This article is protected by copyright. All rights reserved

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhanced Oxygen Evolution and Zinc‐Air Battery Performance via Electronic Spin Modulation in Heterostructured Catalysts

Yang,

He,

Botifoll

et al. 2024

Advanced Materials

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Experimental evidences of the direct influence of external magnetic fields on the mechanism of the electrocatalytic oxygen evolution reaction

Mesa,

Garcés-Pineda,

García-Tecedor

et al. 2024

APL Energy

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The use of magnetic fields as external stimuli to improve the kinetics of electrochemical reactions is attracting substantial attention, given their potential to reduce energy losses. Despite recent reports showing a positive effect on catalytic performance upon applying a magnetic field to a working electrode, there are still many uncertainties and a lack of experimental evidence correlating the presence of the magnetic field to the electrocatalytic performance. Here, we present a combination of electrochemical and spectroscopic tools that demonstrate how the presence of an external magnetic field alters the reaction mechanism of the electrocatalytic oxygen evolution reaction (OER), accelerating the overall performance of a Ni4FeOx electrode. Complementary experimental evidence has been gathered supporting the participation of this microscopic magnetic field effect. Electrochemical impedance spectroscopy (EIS) points to a speed-up of the intrinsic reaction kinetics, independent of other indirect effects. In the same direction, the spectro-electrochemical fingerprint of the intermediate species that appear during the electrocatalytic cycle, as detected under operando conditions, indicates a change in the order of the reaction as a function of hole accumulation. All these experimental data confirm the direct influence of an external magnetic field on the reaction mechanism at the origin of the magnetically enhanced electrocatalytic OER.

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One-pot synthesis of NiFe nanoarrays under an external magnetic field as an efficient oxygen evolution reaction catalyst

Abstract: The NiFe nanoarrays MIL-53(Fe–Ni)/NF-2200Gs was synthesized using a one-pot approach under external magnetic field, and investigated as an efficient OER catalyst in alkaline medium.

Cited by 2 publications

References 51 publications

Enhanced Oxygen Evolution and Zinc‐Air Battery Performance via Electronic Spin Modulation in Heterostructured Catalysts

Enhanced Oxygen Evolution and Zinc‐Air Battery Performance via Electronic Spin Modulation in Heterostructured Catalysts

Experimental evidences of the direct influence of external magnetic fields on the mechanism of the electrocatalytic oxygen evolution reaction

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