{
  "abstract": "In alkaline electrocatalysis, electrostatic theory predicts, and experiments confirm, interfacial acidity that deviates from bulk pHb. The location and magnitude of the proton population within the electric double layer (EDL) and its evolution with catalytic turnover have remained unresolved, leaving a critical gap for mechanistic interpretation across proton-coupled electrocatalysis. Here, using showcase alkaline (pHb 13) hydrogen evolution on Au, electrochemical fluorescence microscopy combined with electrostatic modelling demonstrates an apparent interfacial pH inversion of more than eight units within 1 nm of 1 the electrode, below the outer Helmholtz plane. This EDL proton population is dynamic. At hydrogen-evolution onset, the reaction can draw from it. As electrocatalytic turnover increases, H+ consumption outpaces its electrostatic replenishment, favouring a water-based reaction pathway. Localizing and quantifying this dynamic proton population closes a key gap in the mechanistic interpretation of alkaline hydrogen evolution with a proton-availability framework likely relevant to alkaline electrocatalysis and electrosynthesis at large.",
  "abstract_shown": true,
  "affiliations": [
    "Molecular Spectroscopy Group, Max Planck Institute for Polymer Research, Ackermannweg 10, Mainz, Germany, 55128",
    "PSI Center for Energy & Environmental Sciences, Paul Scherrer Institute, Villigen PSI, Switzerland, CH-5232",
    "CIC energiGUNE,, C/Albert Einstein, 48, Vitoria-Gasteiz (Álava, Spain, 01510",
    "Theory and Computation of Energy Materials (IET-3), Institute of Energy Technologies, Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, Jülich, Germany, 52425",
    "Faculty of Chemistry, Chair of Physical Chemistry II, University of Duisburg-Essen, Universitätsstr. 5, Essen, Germany, 45141"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "name": "Xinwei Zhu"
    },
    {
      "affs": [
        0
      ],
      "name": "Daniel Ohm"
    },
    {
      "affs": [
        0
      ],
      "name": "Qiqi Yang"
    },
    {
      "affs": [
        1
      ],
      "name": "Adrian Heinritz"
    },
    {
      "affs": [
        2
      ],
      "name": "Paramaconi Rodriguez"
    },
    {
      "affs": [
        0
      ],
      "name": "Xiaomin Liu"
    },
    {
      "affs": [
        3,
        4
      ],
      "name": "Tobias Binninger"
    },
    {
      "affs": [
        3,
        4
      ],
      "name": "Katrin F. Domke",
      "orcid": "0000-0002-4562-6088"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/99ger5ppeg8dv.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15009338/v1",
  "fulltext_url": null,
  "id": "99ger5ppeg8dv",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009338/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",
      "2105|Electrocatalysts for Energy Conversion"
    ]
  ],
  "openalex": "W7214096299",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15009338/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-23",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/99ger5ppeg8dv.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:21Z",
      "native_id": "10.26434/chemrxiv.15009338",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009338/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2105|Electrocatalysts for Energy Conversion",
      "subfield": "electrochemistry-energy"
    }
  ],
  "title": "Localizing and quantifying the dynamic interfacial proton population in alkaline electrocatalysis",
  "title_text": "Localizing and quantifying the dynamic interfacial proton population in alkaline electrocatalysis",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:21Z",
  "url": "https://research.draconitic.com/paper/99ger5ppeg8dv",
  "venue": "ChemRxiv",
  "versions": []
}