{
  "abstract": "Geological hydrogen (Geo-H2) generated by water-rock redox reactions could expand low-carbon hydrogen resources by tapping reducing equivalents stored in subsurface minerals. Stimulated Geo-H2 production remains difficult to engineer because the reaction sequence connecting rockhosted Fe2+ release to H2 evolution is incompletely constrained. Here, we support an interfacial sequence linking olivine Fe2+ release, an Fe(II)-bearing hydroxide intermediate state, Fe3O4bearing product growth, and Ni redistribution at evolving Fe-rich interfaces. Across olivine-rich rocks, basalt, and Fe(OH)2 model systems, trace dissolved Ni2+ enhanced H2 evolution over the examined temperatures, reaching rates more than two orders of magnitude above previously reported Geo-H2 systems at comparable temperatures, and dissolved Ni2+ outperformed solid Ni additives under matched additive-form comparisons. Fe-normalized controls show that dissolved Fe2+ alone produced far less H2 than Fe2+ converted to Fe(OH)2, supporting Fe(II)-hydroxide chemistry as a productive gateway to the magnetite-forming pathway. Electron microscopy, spectroscopy, and cross-sectional EDS connected olivine Fe redistribution with Fe-rich alteration products and Ni recruitment, whereas first-principles calculations indicated that adsorbed Ni-Fe sites stabilize dissociated H more strongly. The Ni response was finite, with excess loading suppressing H2 evolution through competing Ni2+ reduction and other high-Ni interfacial inhibitory pathways. These results connect Fe release, hydroxide-associated Fe(II) chemistry, magnetite-bearing product growth, and Ni loading and accessibility, providing an interfacial framework for promoting water reduction in stimulated Geo-H2 systems.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Materials Science and Engineering",
    "Massachusetts Institute of Technology",
    "Department of Nuclear Science and Engineering"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Yifan Gao"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Jakob Krogh Nielsen"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Seok Hee Han"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Ming Lei"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Haihui Lan"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Yuheng Wu"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "William Gilstrap"
    },
    {
      "affs": [
        0,
        1,
        2
      ],
      "name": "Ju Li"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Iwnetim I. Abate"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/c6x03mz8s5j7b.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15009395/v1",
  "fulltext_url": null,
  "id": "c6x03mz8s5j7b",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009395/v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2305|CO2 Sequestration and Geologic Interactions"
    ]
  ],
  "openalex": "W7214164466",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15009395/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-23",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/c6x03mz8s5j7b.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:21Z",
      "native_id": "10.26434/chemrxiv.15009395",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009395/v1"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "openalex:2305|CO2 Sequestration and Geologic Interactions",
      "subfield": "environmental-science"
    }
  ],
  "title": "Dynamic Ni–Fe Interfaces Regulate Stimulated Geological Hydrogen Production",
  "title_text": "Dynamic Ni–Fe Interfaces Regulate Stimulated Geological Hydrogen Production",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:21Z",
  "url": "https://research.draconitic.com/paper/c6x03mz8s5j7b",
  "venue": "ChemRxiv",
  "versions": []
}