{
  "abstract": "Water dissociation (WD) at bipolar membrane (BPM) junctions is a key reaction in a number of electrochemical energy conversion and separation technologies. While metal oxide catalysts like SnO 2 accelerate WD, conventional particle-based deposition methods typically yield thick and morphologically heterogeneous junction layers. We report a simple aqueous precursor-treatment route that reconstructs the near-surface region of Nafion into an ultrathin SnO 2 -bearing interface. In contrast to conventional spin-coated SnO 2 , which forms a discrete particulate overlayer, the embedded interface is smooth, spatially confined, and closely integrated with the membrane. Despite this major structural difference, BPMs fabricated from SnO 2 -eb-Nafion exhibit WD performance comparable to benchmark spin-coated SnO 2 junctions. When normalized by SnO 2 loading, the embedded junction delivers a ~21-fold higher current density in an electrolyzer test cell at a total cell voltage of 2 V, highlighting improved catalyst utilization. Structural and electrochemical controls show that the high activity arises from interfacially localized SnO 2 rather than bulk SnO 2 incorporation or altered proton conductivity. The embedded route improves precursor efficiency, increases membrane junction adhesion force by 7×, and maintains stable operation under continuous elec-trolyzer testing. A preliminary pseudo-PEM water-electrolysis demonstration further shows that the embedded SnO 2 interface remains beneficial in an AEI–PEM heterojunction architecture coupled to a PGM-free Co 3 O 4 anode. These results establish precursor-based interfacial self-reconstruction as a practical route to thin, active, and mechanically integrated catalyst–membrane junctions. Keywords: Bipolar membranes; Water dissociation; Tin oxide (SnO 2 ); Ionomer interfaces; Water electrolysis",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemical & Biomolecular Engineering and Department of Chemistry",
    "University of California",
    "Energy Technologies and Systems Division",
    "Lawrence Berkeley National Laboratory",
    "Department of Chemical and Biomolecular Engineering",
    "University of Pennsylvania",
    "National Fuel Cell Research Center (NFCRC",
    "Department of Mechanical and Materials Engineering",
    "Florida International University",
    "Department of Chemistry and Biochemistry and the Oregon Center for Electrochemistry",
    "University of Oregon"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 16,
  "authors": [
    {
      "affs": [
        0,
        1,
        2,
        3
      ],
      "name": "Yifan Wu"
    },
    {
      "affs": [
        4,
        5
      ],
      "name": "Benjamin N. Indeglia"
    },
    {
      "affs": [
        4,
        1,
        6
      ],
      "name": "Vivek S. Devalla"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Wenbo Zhang"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Helen K. Chen"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Peiyao Wu"
    },
    {
      "affs": [
        7,
        8
      ],
      "name": "Sahil Gasso"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Jihan Zhang"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Yu-Wei Chuang"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Duha Syar"
    },
    {
      "affs": [
        9,
        10
      ],
      "name": "Olivia T. Vulpin"
    },
    {
      "affs": [
        7,
        8
      ],
      "name": "Daniela Radu"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Joelle Frechette"
    },
    {
      "affs": [
        4,
        1,
        6
      ],
      "name": "Iryna V. Zenyuk"
    },
    {
      "affs": [
        4,
        5
      ],
      "name": "Karen I. Winey"
    },
    {
      "affs": [
        0,
        1,
        2,
        3,
        9,
        10
      ],
      "name": "Shannon W. Boettcher",
      "orcid": "0000-0001-8971-9123"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4e7qcjzg91nvv.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15009776/v1",
  "fulltext_url": null,
  "id": "4e7qcjzg91nvv",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009776/v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2208|Fuel Cells and Related Materials"
    ]
  ],
  "openalex": "W7216507248",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15009776/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-02",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/4e7qcjzg91nvv.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:21Z",
      "native_id": "10.26434/chemrxiv.15009776",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009776/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "source:chemrxiv",
      "subfield": "general"
    }
  ],
  "title": "An Ultrathin Embedded SnO2 Interface for Water Dissociation in Bipolar Membranes and pseudo-PEM Electrolyzers",
  "title_text": "An Ultrathin Embedded SnO2 Interface for Water Dissociation in Bipolar Membranes and pseudo-PEM Electrolyzers",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:21Z",
  "url": "https://research.draconitic.com/paper/4e7qcjzg91nvv",
  "venue": "ChemRxiv",
  "versions": []
}