{
  "abstract": "Tandem photoelectrochemical (PEC) cells made exclusively of earth-abundant oxides are a promising route to solar hydrogen, but bias-free operation and durability remain challenging, particularly in acidic environments. This work presents a 1 cm2 zero-gap tandem PEC cell, operated without housing and fed only with deionized water, that integrates an electrodeposited nanostructured WO3 photoanode (band gap 2.75 eV), a spray-coated nanostructured CuFe2O4 photocathode (1.43 eV) and a Nafion 117 proton-exchange membrane acting as solid electrolyte and separator. Mott–Schottky analysis in N2-purged 0.1 M HClO4 confirms the expected n-type and p-type semiconductor character, with a band-edge alignment compatible with unassisted operation. Under simulated AM 1.5G sunlight, the device delivers ≈42 µA cm−2 at zero bias (solar-to-hydrogen efficiency ≈ 0.05%, assuming unity Faradaic efficiency) and a saturated photocurrent density of 0.47 mA cm−2 at −1.0 V (throughput efficiency 0.70%). After 96 h of operation (48 h at 0 V and 48 h at −0.7 V), the photocurrent decreases by only ≈5–6%. Impedance spectroscopy and distribution of relaxation times analysis identify a dominant millisecond-scale interfacial charge-transfer process. Post-operando analyses reveal that WO3 undergoes only mild surface reduction, whereas CuFe2O4 shows partial Cu2+ → Cu+ reduction and local delamination, identifying the photocathode as the lifetime-limiting component.",
  "abstract_shown": true,
  "affiliations": [
    "Institute for Advanced Energy Technologies “Nicola Giordano” (ITAE), National Research Council of Italy (CNR), Via Salita S. Lucia Sopra Contesse 5, 98126 Messina, Italy"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 3,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Rossana Giaquinta",
      "orcid": "0009-0009-9532-7092"
    },
    {
      "affs": [
        0
      ],
      "name": "Carmine Arnese"
    },
    {
      "affs": [
        0
      ],
      "name": "Stefano Trocino",
      "orcid": "0000-0003-2418-146X"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/0p4jwnakrdaw6.bib",
  "cited_by": 0,
  "doi": "10.3390/nano16211415",
  "fulltext_url": null,
  "id": "0p4jwnakrdaw6",
  "issns": [
    "2079-4991"
  ],
  "landing_url": "https://www.mdpi.com/2079-4991/16/21/1415",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [],
  "openalex": null,
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-03",
  "publisher": "MDPI AG",
  "ris": "https://research.draconitic.com/paper/0p4jwnakrdaw6.ris",
  "sources": [
    {
      "first_seen": "2026-11-04T00:24:14Z",
      "native_id": "10.3390/nano16211415",
      "source": "crossref",
      "url": "https://www.mdpi.com/2079-4991/16/21/1415"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "issn:2079-4991",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Zero-Gap Tandem Photoelectrochemical Cell Based on Nanostructured WO3 and CuFe2O4 Photoelectrodes and a Proton-Exchange Membrane: Bias-Free Photoelectrochemical Operation and Degradation Analysis",
  "title_text": "Zero-Gap Tandem Photoelectrochemical Cell Based on Nanostructured WO3 and CuFe2O4 Photoelectrodes and a Proton-Exchange Membrane: Bias-Free Photoelectrochemical Operation and Degradation Analysis",
  "type": "peer-reviewed",
  "updated_at": "2026-11-05T00:20:54Z",
  "url": "https://research.draconitic.com/paper/0p4jwnakrdaw6",
  "venue": "Nanomaterials",
  "versions": []
}