Localized high-entropy oxide boosts oxygen evolution for efficient water splitting and seawater-based zinc–air batteries
image: Schematical illustration of the localized high-entropy engineering strategy to improve iron-based OER electrocatalysts for renewable energy technologies in water splitting and Zn–air battery (ZAB).
Credit: Liang Qiu, Baowen Zhou, Ying Li, Muhammad Imran Abdullah, Zhaosong Wu, Jianqing Chen, Wanglan Zhou, Tingting Ren, Yuqi Wang & Zhen Huang.
Researchers from Shanghai Jiao Tong University introduce a nanoscale localized high-entropy engineering strategy that dramatically lowers the energy barrier for oxygen evolution reaction, outperforming costly precious metal benchmarks.
The urgent global shift toward clean energy depends heavily on scalable technologies like water electrolysis for green hydrogen production and rechargeable metal-air batteries for energy storage. However, these systems are fundamentally bottlenecked by the oxygen evolution reaction (OER)—a sluggish four-electron transfer process requiring substantial energy to proceed. While precious metal oxides such as RuO₂ and IrO₂ serve as conventional benchmark catalysts, their extreme scarcity and prohibitive costs render them impractical for terawatt-scale industrial deployment.
To address this challenge, a research team from Shanghai Jiao Tong University has developed a novel localized high-entropy oxide (LHEO) strategy. By spatially confining a nanoscale high-entropy oxide containing five earth-abundant metals (Fe, Co, Ni, Zn, and Mn) within hematite (α-Fe₂O₃), the team created a unique α-Fe₂O₃@LHEO nanoarchitecture that breaks through traditional performance limitations of non-noble metal catalysts. The findings were published in ENGINEERING Energy.
Key Research Highlights & Achievements
- Exceptional Catalytic Activity: The α-Fe₂O₃@LHEO catalyst achieves a current density of 10 mA/cm² at an exceptionally low overpotential of 229 mV with a small Tafel slope of 34.4 mV/dec in alkaline water splitting, significantly outperforming commercial RuO₂ (326 mV, 118.8 mV/dec).
- Ultra-Long Stability: The catalyst operates continuously for over 1,000 hours at a demanding current density of 100 mA/cm² without noticeable activity degradation, solving the long-standing activity-stability trade-off in iron-based electrocatalysts.
- Superior Seawater Battery Performance: Integrated as an air cathode in rechargeable zinc-air batteries powered by natural seawater, the system delivers a high peak power density of 88.3 mW/cm² and stable operation over 600 cycles, far exceeding commercial Ru-Pt benchmark electrocatalysts (74.7 mW/cm², 170 cycles).
- Fundamental Mechanism Shift: Advanced spectroscopy and density functional theory (DFT) calculations reveal that the localized high-entropy effect induces lattice strain, modulates electronic structure, and stabilizes high-spin Fe³⁺ centers. This lowers the energy barrier and successfully shifts the catalytic pathway from the conventional adsorbate evolution mechanism (AEM) to the energetically favorable lattice oxygen mechanism (LOM), reducing the rate-determining step barrier from 1.85 eV to 1.71 eV.
Bridging Atomic Engineering to Sustainable Applications
Iron-based materials have long been ideal candidates for commercial electrolysis due to their natural abundance and rich redox chemistry. However, poor electrical conductivity and difficulty maintaining active spin states under working conditions have historically limited their efficiency.
By introducing localized high-entropy atomic disorder, the research team modified the local coordination environment of iron. The resulting lattice contraction and downshifted Fe d-band center weaken intermediate adsorption strength while boosting intrinsic electrical conductivity. When deployed in both liquid seawater zinc-air batteries and flexible all-solid-state zinc-air devices (F-ZAB), the catalyst demonstrated robust mechanical flexibility and high energy efficiency.
This nanoscale localized high-entropy engineering strategy establishes a powerful new paradigm for designing highly efficient, durable, and cost-effective electrocatalysts using abundant earth elements.
About the Research
Journal: ENGINEERING Energy
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Cite this article: Qiu, L., Zhou, B., Li, Y., Abdullah, M. I., Wu, Z., Chen, J., Zhou, W., Ren, T., Wang, Y., & Huang, Z. (2026). Localization of high-entropy metal oxide in iron oxide nanoparticles for efficient oxygen evolution reaction. ENGINEERING Energy, 20(2), 10670. https://doi.org/10.1007/s11708-026-1067-z