Electronic modulation in a defect-rich high-entropy NiCoFeCu LDH enables accelerated oxygen evolution

Chengshuo Du; Shuxing Bai; Mingrui Guo; Chengshuo Du; Shuxing Bai; Mingrui Guo

doi:10.3934/energy.2026025

AIMS Energy

2026, Volume 14, Issue 3: 602-617. doi: 10.3934/energy.2026025

Previous Article Next Article

Research article Topical Sections

Electronic modulation in a defect-rich high-entropy NiCoFeCu LDH enables accelerated oxygen evolution

College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, Shandong, P. R. China

Received: 01 April 2026 Revised: 15 May 2026 Accepted: 22 May 2026 Published: 26 May 2026

Accelerating the oxygen evolution reaction (OER) is critical for efficient alkaline water electrolysis in green hydrogen production. Rational regulation of the electronic structure of transition metal (oxy)hydroxides offers a vital route to enhance their OER kinetics under alkaline conditions. Herein, we reported a defect-rich high-entropy layered double hydroxide, D-NiCoFeCu-LDH, constructed via a sequential electrodeposition–electrochemical etching strategy. Selective chromium leaching reconstructs a homogeneous Ni–Co–Fe–Cu high-entropy matrix while introducing abundant vacancies and lattice distortion. Structural characterization confirms uniform elemental distribution and defect-enriched nanosheet arrays, whereas X-ray photoelectron spectroscopy (XPS) analysis reveals pronounced electronic redistribution, manifested by increased high-valence Ni³⁺/Co³⁺ species and positive binding energy shifts. We proposed that highly dispersed Cu⁺/Cu²⁺ species act as electronic modulators, withdrawing electron density from neighboring Ni, Co, and Fe centers, while lattice distortion further promotes electronic reconfiguration. Electrochemical measurements demonstrated enhanced intrinsic activity and accelerated charge-transfer kinetics compared to quaternary counterparts. Importantly, in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) directly verified facilitated ^*OOH intermediate formation at lower overpotential, establishing a molecular-level link between electronic modulation and improved OER kinetics. In this work, we provide mechanistic insight into how synergistic high-entropy regulation and defect engineering cooperatively enhance intrinsic catalytic activity, offering a framework for designing durable, high-performance OER electrocatalysts.
- high-entropy materials,
- layered double hydroxide,
- electronic structure modulation,
- defect engineering,
- oxygen evolution reaction
Citation: Chengshuo Du, Shuxing Bai, Mingrui Guo. Electronic modulation in a defect-rich high-entropy NiCoFeCu LDH enables accelerated oxygen evolution[J]. AIMS Energy, 2026, 14(3): 602-617. doi: 10.3934/energy.2026025

Related Papers:

Abstract

Accelerating the oxygen evolution reaction (OER) is critical for efficient alkaline water electrolysis in green hydrogen production. Rational regulation of the electronic structure of transition metal (oxy)hydroxides offers a vital route to enhance their OER kinetics under alkaline conditions. Herein, we reported a defect-rich high-entropy layered double hydroxide, D-NiCoFeCu-LDH, constructed via a sequential electrodeposition–electrochemical etching strategy. Selective chromium leaching reconstructs a homogeneous Ni–Co–Fe–Cu high-entropy matrix while introducing abundant vacancies and lattice distortion. Structural characterization confirms uniform elemental distribution and defect-enriched nanosheet arrays, whereas X-ray photoelectron spectroscopy (XPS) analysis reveals pronounced electronic redistribution, manifested by increased high-valence Ni³⁺/Co³⁺ species and positive binding energy shifts. We proposed that highly dispersed Cu⁺/Cu²⁺ species act as electronic modulators, withdrawing electron density from neighboring Ni, Co, and Fe centers, while lattice distortion further promotes electronic reconfiguration. Electrochemical measurements demonstrated enhanced intrinsic activity and accelerated charge-transfer kinetics compared to quaternary counterparts. Importantly, in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) directly verified facilitated ^*OOH intermediate formation at lower overpotential, establishing a molecular-level link between electronic modulation and improved OER kinetics. In this work, we provide mechanistic insight into how synergistic high-entropy regulation and defect engineering cooperatively enhance intrinsic catalytic activity, offering a framework for designing durable, high-performance OER electrocatalysts.

References

[1]	Hoang AL, Balakrishnan S, Hodges A, et al. (2023) High-performing catalysts for energy-efficient commercial alkaline water electrolysis. Sustainable Energy Fuels 7: 31–60. https://doi.org/10.1039/d2se01197b doi: 10.1039/d2se01197b
[2]	Tuysuz H (2024) Alkaline water electrolysis for green hydrogen production. Acc Chem Res 57: 558–567. https://doi.org/10.1021/acs.accounts.3c00709 doi: 10.1021/acs.accounts.3c00709
[3]	Wang W, Yang B, Zhang H, et al. (2025) Novel synthesis of amorphous/defect-rich NiFe(O)OH nanosheets for alkaline electrolyzers at high current density. Next Mater 9: 101232. https://doi.org/10.1016/j.nxmate.2025.101232 doi: 10.1016/j.nxmate.2025.101232
[4]	Jia H, Yao N, Zhu J, et al. (2023) Reconstructured electrocatalysts during oxygen evolution reaction under alkaline electrolytes. Chemistry 29: e202203073. https://doi.org/10.1002/chem.202203073 doi: 10.1002/chem.202203073
[5]	Park H, Park BH, Choi J, et al. (2020) Enhanced electrochemical properties and OER performances by Cu substitution in NiCo₂O₄ spinel structure. Nanomaterials (Basel) 10: 1727. https://doi.org/10.3390/nano10091727 doi: 10.3390/nano10091727
[6]	Bai J, Chen C, Lian Y, et al. (2024) Role of amorphous engineering and cerium doping in NiFe oxyhydroxide for electrocatalytic water oxidation. J Colloid Interface Sci 663: 280–286. https://doi.org/10.1016/j.jcis.2024.02.093 doi: 10.1016/j.jcis.2024.02.093
[7]	Li J, Wei Y, Zou L, et al. (2025) Cu dual-site doping: synergistic enhancement of OER activity through LDH and nickel foam interface engineering. New J Chem 49: 17577–17587. https://doi.org/10.1039/d5nj03068d doi: 10.1039/d5nj03068d
[8]	Sharma L, Katiyar NK, Parui A, et al. (2021) Low-cost high entropy alloy (HEA) for high-efficiency oxygen evolution reaction (OER). Nano Res 15: 4799–4806. https://doi.org/10.1007/s12274-021-3802-4 doi: 10.1007/s12274-021-3802-4
[9]	Ma Y, Ma Y, Wang Q, et al. (2021) High-entropy energy materials: Challenges and new opportunities. Energy Environ Sci 14: 2883–2905. https://doi.org/10.1039/d1ee00505g doi: 10.1039/d1ee00505g
[10]	Tomboc GM, Zhang X, Choi S, et al. (2022) Stabilization, characterization, and electrochemical applications of high-entropy oxides: Critical assessment of crystal phase–properties relationship. Adv Funct Mater 32: 2205142. https://doi.org/10.1002/adfm.202205142 doi: 10.1002/adfm.202205142
[11]	Liang J, Cao G, Zeng M, et al. (2024) Controllable synthesis of high-entropy alloys. Chem Soc Rev 53: 6021–6041. https://doi.org/10.1039/d4cs00034j doi: 10.1039/d4cs00034j
[12]	Ding Y, Wang Z, Liang Z, et al. (2025) A monolayer high-hntropy layered hydroxide frame for efficient oxygen evolution reaction. Adv Mater 37: e2302860. https://doi.org/10.1002/adma.202302860 doi: 10.1002/adma.202302860
[13]	Jeung Y, Jung H, Kim D, et al. (2021) 2D-structured V-doped Ni(Co, Fe) phosphides with enhanced charge transfer and reactive sites for highly efficient overall water splitting electrocatalysts. J Mater Chem A 9: 12203–12213. https://doi.org/10.1039/d1ta02149d doi: 10.1039/d1ta02149d
[14]	Yan Y, Li P, Zhang Z, et al. (2024) Interfacial Si–O coordination for inhibiting the graphite phase enables superior SiC/Nb heterostructure joining by AuNi. Composites Part B 282: 111557. https://doi.org/10.1016/j.compositesb.2024.111557 doi: 10.1016/j.compositesb.2024.111557
[15]	Yang T, Yan Y, Liu R, et al. (2025) Engineering twins within lattice-matched Co/CoO heterostructure enables efficient hydrogen evolution reactions. Nano Lett 25: 7707–7715. https://doi.org/10.1021/acs.nanolett.5c00472 doi: 10.1021/acs.nanolett.5c00472
[16]	Wang R, Yang Y, Xu X, et al. (2023) Interface engineering and heterometal-doped FeOOH/Ga-Ni₃S₂nanosheet arrays for efficient electrocatalytic oxygen evolution. Inorg Chem Front 10: 1348–1356. https://doi.org/10.1039/d2qi02081e doi: 10.1039/d2qi02081e
[17]	Ma H, Chen Z, Wang Z, et al. (2022) Interface engineering of Co/CoMoN/NF heterostructures for high-performance electrochemical overall water splitting. Adv Sci (Weinh) 9: e2105313. https://doi.org/10.1002/advs.202105313 doi: 10.1002/advs.202105313
[18]	Hou J, Sun Y, Wu Y, et al. (2018) Promoting active sites in core–shell nanowire array as mott–schottky electrocatalysts for efficient and stable overall water splitting. Adv Funct Mater 28: 1704447. https://doi.org/10.1002/adfm.201704447 doi: 10.1002/adfm.201704447
[19]	Yu L, Zhou H, Sun J, et al. (2017) Cu nanowires shelled with NiFe layered double hydroxide nanosheets as bifunctional electrocatalysts for overall water splitting. Energy Environ Sci 10: 1820–1827. https://doi.org/10.1039/c7ee01571b doi: 10.1039/c7ee01571b
[20]	Wu Y, Xu L, Xin W, et al. (2021) Rational construction of 3D MoNi/NiMoOx@NiFe LDH with rapid electron transfer for efficient overall water splitting. Electrochim Acta 369: 137680. https://doi.org/10.1016/j.electacta.2020.137680 doi: 10.1016/j.electacta.2020.137680
[21]	Sang Y, Cao X, Wang L, et al. (2020) Facile synthesis of three-dimensional spherical Ni(OH)₂/NiCo₂O₄ heterojunctions as efficient bifunctional electrocatalysts for water splitting. Int J Hydrogen Energy 45: 30601–30610. https://doi.org/10.1016/j.ijhydene.2020.08.097 doi: 10.1016/j.ijhydene.2020.08.097
[22]	Yuan F, Wei J, Qin G, et al. (2020) Carbon cloth supported hierarchical core-shell NiCo₂S₄@CoNi-LDH nanoarrays as catalysts for efficient oxygen evolution reaction in alkaline solution. J Alloys Compd 830: 154658. https://doi.org/10.1016/j.jallcom.2020.154658 doi: 10.1016/j.jallcom.2020.154658
[23]	Niu Y, Li W, Wu X, et al. (2019) Amorphous nickel sulfide nanosheets with embedded vanadium oxide nanocrystals on nickel foam for efficient electrochemical water oxidation. J Mater Chem A 7: 10534–10542. https://doi.org/10.1039/c8ta12483c doi: 10.1039/c8ta12483c
[24]	Huo M, Liang Y, Qin K, et al. (2024) Hexavalent iridium boosts oxygen evolution performance. Green Carbon 2: 403–404. https://doi.org/10.1016/j.greenca.2024.07.003 doi: 10.1016/j.greenca.2024.07.003
[25]	Shu W, Sun Q, Huang K, et al. (2024) V-Doping induced surface electron modulation and nanostructure design for Ni(OH)₂/GO towards efficient urea electro-oxidation. Chem Commun (Camb) 60: 13267–13270. https://doi.org/10.1039/d4cc04157g doi: 10.1039/d4cc04157g
[26]	Zhang L, Cai W, Bao N (2021) Top-level design strategy to construct an advanced high-entropy Co-Cu-Fe-Mo (oxy)hydroxide electrocatalyst for the oxygen evolution reaction. Adv Mater 33: e2100745. https://doi.org/10.1002/adma.202100745 doi: 10.1002/adma.202100745
[27]	Zhang W, He X, Pan P, et al. (2025) Cr-enhanced selective dealloying and sequential electrochemical reconstruction to tailor NiFe-based integrated catalysts for industrial-level water oxidation. Energy Environ Sci 18: 8697–8707. https://doi.org/10.1039/d5ee03448e doi: 10.1039/d5ee03448e
[28]	Wang L, Gao Z, Su K, et al. (2024) Stacked high‐entropy hydroxides promote charge transfer kinetics for photoelectrochemical water splitting. Adv Funct Mater 34: 2403948. https://doi.org/10.1002/adfm.202403948 doi: 10.1002/adfm.202403948
[29]	Zhong X, Wang HY, Zhang C, et al. (2025) High‐valence metal modulating lattice oxygen in high‐entropy layered double hydroxides for enhanced oxygen evolution reaction. Adv Funct Mater 35: e18240. https://doi.org/10.1002/adfm.202518240 doi: 10.1002/adfm.202518240
[30]	Li X, Wang J, Xue H, et al. (2025) Tuning α‐MnOOH formation via atomic‐level Fe introduction for superior OER performance. Adv Funct Mater 35: 2503360. https://doi.org/10.1002/adfm.202503360 doi: 10.1002/adfm.202503360
[31]	Chang R, Pang Y, Yang Q, et al. (2025) High entropy hydroxide with a hollow nanocage structure promotes efficient and stable water/seawater electro-oxidation. Chem Sci 16: 11961–11969. https://doi.org/10.1039/d5sc01961c doi: 10.1039/d5sc01961c
[32]	Wang F, Feng L, Zhang M, et al. (2025) Engineering oxygen nonbonding states in high entropy hydroxides for scalable water oxidation. Nat Commun 16: 6624. https://doi.org/10.1038/s41467-025-61766-2 doi: 10.1038/s41467-025-61766-2
[33]	Yang H, Li F, Zhan S, et al. (2026) Metal-hydroxyls mediate intramolecular proton transfer in heterogeneous O-O bond formation. Nat Chem 18: 335–344. https://doi.org/10.1038/s41557-025-01993-8 doi: 10.1038/s41557-025-01993-8
[34]	Zhang Y, Zheng T, Dai H, et al. (2025) Lattice oxygen-mediated water oxidation on reconstructed Ni₃S₂/NiFeOOH heterointerfaces. Chemistry, e03063. https://doi.org/10.1002/chem.202503063 doi: 10.1002/chem.202503063

Reader Comments

Your name:*

Email:*
© 2026 the Author(s), licensee AIMS Press. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0)