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This study aims to enhance the catalytic performance of layered double hydroxides (LDHs) for overall water splitting.

May 26, 2026Open Access

Oxygen‐Vacancy‐Engineered Ni‐Fe Layered Double Hydroxides Enables Ultralow‐Overpotential Hydrogen Evolution Reaction and Durable Overall Water Splitting

QLQi LiuHefei University of Technology ZDZhiling DuHebei University of Engineering LWLei WuHefei University of Technology

Key Points

This study aims to enhance the catalytic performance of layered double hydroxides (LDHs) for overall water splitting.
Constructed ultrathin Ni-Fe LDH nanosheets via one-step hydrothermal synthesis followed by mild NaBH4 etching.
Characterized materials using XRD, XPS, and EPR to analyze structural and electronic properties.
Conducted in situ Raman and DFT analyses to understand active sites and energy barriers.
Achieved an ultralow HER overpotential of 37 mV at 10 mA cm−2 and an OER overpotential of 315 mV at 50 mA cm−2.
Demonstrated durability by sustaining 500 mA cm−2 for over 150 hours with negligible decay.
DFT analysis showed oxygen vacancies optimize intermediate adsorption, lowering energy barriers.

Abstract

ABSTRACT Layered double hydroxides (LDHs) are attractive non‐noble catalysts for overall water splitting (OWS), yet their hydrogen evolution reaction (HER) activity is often limited by suboptimal *H adsorption and a paucity of accessible sites. Herein, we introduce an oxygen‐vacancy (O v ) engineering strategy to construct ultrathin Ni‐Fe LDH nanosheets through one‐step hydrothermal synthesis followed by mild NaBH 4 etching. The resulting O v ‐rich Ni‐Fe LDH exhibits expanded interlayer spacing and abundant coordinatively unsaturated metal sites, as confirmed by XRD, XPS/O 1s deconvolution, and a pronounced electron paramagnetic resonance (EPR) signal at g ≈ 2.003. Benefiting from the nanosheet architecture and defect modulation, the catalyst delivers an ultralow HER overpotential of 37 mV at 10 mA cm −2 and an oxygen evolution reaction (OER) overpotential of 315 mV at 50 mA cm −2 . A two‐electrode alkaline electrolyzer assembled from the same material achieves 10 mA cm −2 at 1.54 V and sustains 500 mA cm −2 for > 150 h with negligible decay, underscoring practical durability. In situ Raman reveals an earlier formation of the active NiFeOOH phase under anodic polarization, whereas DFT identifies Ni sites as the dominant centers and shows that O v upshifts the d‐band (HER) and downshifts it (OER) to optimize intermediate adsorption/desorption, lowering the rate‐determining energy barriers. This study proposes a feasible approach for fabricating LDH‐based electrocatalysts with enhanced catalytic performance in sustainable and clean energy conversion.

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