{
  "abstract": "High-entropy oxides (HEOs) have emerged as promising electrocatalysts owing to their unique cocktail effect, which enables synergistic multielement interactions, leading to enhanced catalytic activity. In this work, three novel non-equimolar high-entropy spinel ferrites-based materials, (M0.3Ni0.21Cu0.21Co0.14Mn0.14)Fe₂O₄ (M = Fe, Mg, or Zn)-Gd0.1Ce0.9O1.95 (GDC), have been adopted as anodes for direct-ammonia solid oxide fuel cells (DA-SOFCs). Synchrotron-based X-ray absorption spectroscopy (XAS) and micro-computed tomography (Micro-CT) were employed, alongside X-ray diffraction (XRD), inductively coupled plasma-optical emission spectroscopy (ICP-OES), scanning electron microscopy (SEM), scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy (STEM-EDX), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy, for comprehensive characterization. The XRD analysis showed that the HEO(Zn) and HEO(Mg) samples exhibited a single-phase high-entropy spinel ferrite, whereas the d-HEO(Fe) displayed a dual-phase structure comprising a predominant spinel phase (90.9 wt%) and a minor hematite (Fe₂O₃) phase. The HEO samples were treated in a reducing atmosphere to form a composite with a monometallic Fe phase (>82.4 wt%) and FeNiCu alloy. Extended X-ray absorption fine structure spectroscopy (EXAFS) analysis revealed that the Fe³⁺, Cu²⁺, Ni²⁺, and Co²⁺ cations are distributed between the octahedral and tetrahedral coordination environments within d-HEO(Fe) sample, while the Mn³⁺ ions are located at the octahedral sites. The lanthanum strontium gallium magnesium oxide (LSGM) electrolyte-supported cell with a d-HEO(Fe) anode achieved the highest peak power density (PPD) of nearly 382.0 mW/cm² at 850 °C, whereas the SOFCs with HEO(Zn) and HEO(Mg) anodes delivered lower PPD values of 218.3 and 195.7 mW/cm², respectively. Notably, the cell with the d-HEO(Fe) anode demonstrated excellent durability for over 75 h at 800 °C, with only 3.16% voltage degradation. Density functional theory (DFT) computations were carried out to scrutinize the NH₃ decomposition mechanism on the Fe(110) surface, which represents the reduced HEO anode, and were benchmarked against those on the Ni(111) surface. Interestingly, the formation of the N₂* species via recombination of N* atoms is identified as the rate-controlling step for NH₃ cracking on Fe(110) and Ni(111), exhibiting the highest activation barriers of 2.43 and 1.63 eV, respectively, among all elementary steps considered.",
  "abstract_shown": true,
  "affiliations": [
    "CSIRO Energy Clayton South Victoria Australia.",
    "Department of Chemical and Biological Engineering Monash University Clayton Victoria Australia."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Omer Elmutasim",
      "orcid": "0009-0008-2359-2199"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Maxwell P Pinczes",
      "orcid": "0009-0008-6837-6609"
    },
    {
      "affs": [
        0
      ],
      "name": "Dattatray S Dhawale",
      "orcid": "0000-0003-0028-8879"
    },
    {
      "affs": [
        0
      ],
      "name": "Sarbjit Giddey",
      "orcid": "0000-0002-8342-2895"
    },
    {
      "affs": [
        1
      ],
      "name": "Sankar Bhattacharya",
      "orcid": "0000-0002-7590-6814"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/240rqxf3xzdye.bib",
  "cited_by": 0,
  "doi": "10.1002/smsc.70427",
  "fulltext_url": "https://europepmc.org/articles/PMC13687658",
  "id": "240rqxf3xzdye",
  "issns": [
    "2688-4046"
  ],
  "landing_url": "https://europepmc.org/article/MED/42923066",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2505|Advancements in Solid Oxide Fuel Cells"
    ]
  ],
  "openalex": "W7223178104",
  "pdf_url": "https://europepmc.org/articles/PMC13687658?pdf=render",
  "pmcid": "PMC13687658",
  "pmid": "42923066",
  "published": "2026-10-21",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/240rqxf3xzdye.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:33Z",
      "native_id": "MED:42923066",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42923066"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2505|Advancements in Solid Oxide Fuel Cells",
      "subfield": "electrochemistry-energy"
    }
  ],
  "title": "Non-Equimolar High-Entropy Spinel Oxides as Anode Materials for a Direct Ammonia-Fed Solid Oxide Fuel Cell.",
  "title_text": "Non-Equimolar High-Entropy Spinel Oxides as Anode Materials for a Direct Ammonia-Fed Solid Oxide Fuel Cell.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:20:33Z",
  "url": "https://research.draconitic.com/paper/240rqxf3xzdye",
  "venue": "Small science",
  "versions": []
}