{
  "abstract": "Photocatalytic oxygen reduction to hydrogen peroxide (H2O2) over stable, earthabundant materials is attractive for solar energy conversion. The question how photocatalyst morphology governs photocatalytic performance remains, however, poorly understood, as the contributions of surface area and charge-carrier dynamics are convoluted. Herein, we investigate a series of hard-templated hollow potassium poly(heptazine imide) (PHI) spheres (KPHIS) with varying shell thickness and porosity. The photocatalytic H2O2 production is benchmarked against bulk KPHI and correlated with excited-state dynamics probed by steadystate and time-resolved photoluminescence and femtosecond transient absorption spectroscopy under quencher-free and donor-containing conditions. Notably, whilst all KPHIS outperform bulk KPHI, the activity varies non-monotonically with shell thickness and excitation wavelength, whereby the thickest-shelled sphere ‒ not the one with the highest specific surface area and pore volume ‒ is most active at 365 and 406 nm, with apparent quantum yields up to ~3.9%. These experiments reveal that the activity is governed not by porosity alone but by the kinetic competition between donor-mediated hole extraction (least efficient in the most porous sample at low wavelength irradiation) and stabilization of long-lived reduced states that drive O2 reduction. Shell thickness should be co-optimized with light penetration depth and donorconditioned charge dynamics, rather than maximizing porosity alone.",
  "abstract_shown": true,
  "affiliations": [
    "Institute of Electrochemistry Ulm University Albert-Einstein-Allee 47",
    "Institute for Technical Chemistry and Environmental Chemistry, Faculty of Chemistry and Earth Sciences",
    "Friedrich Schiller University Jena Philosophenweg",
    "Institute for Physical Chemistry",
    "Schiller University Jena Helmholtzweg",
    "Department Functional Interfaces Leibniz Institute of Photonic Technology (Leibniz-IPHT",
    "Albert-Einstein-Straße",
    "Institute of Organic Chemistry and Macromolecular Chemistry (IOMC",
    "Friedrich Schiller University Jena Lessingstraße",
    "Center for Energy and Environmental Chemistry Jena (CEEC Jena",
    "Jena Center for Soft Matter Friedrich Schiller University Jena Philosophenweg",
    "Institute of Inorganic and Analytical Chemistry Friedrich-Schiller-University Jena Humboldtstraße",
    "Helmholtz Institute for Polymers in Energy Applications Jena (HIPOLE Jena, Lessingstraße 12–14, Jena, Germany, 07743",
    "Leibniz Institute of Surface Engineering (Leibniz-IOM, Permoserstraße 15, Leipzig, Germany, 04318",
    "Felix-Bloch-Institute of Solid State Physics University Leipzig Linnéstraße"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 12,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Alexander Lange"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Lingli Ni"
    },
    {
      "affs": [
        3,
        4
      ],
      "name": "Arindam Konar"
    },
    {
      "affs": [
        5,
        6
      ],
      "name": "Andreas Stihl"
    },
    {
      "affs": [
        7,
        8
      ],
      "name": "Dariusz Mitoraj"
    },
    {
      "affs": [
        9
      ],
      "name": "Marius Hermesdorf"
    },
    {
      "affs": [
        2
      ],
      "name": "Desirée Leistenschneider"
    },
    {
      "affs": [
        10
      ],
      "name": "Andrea Pannwitz"
    },
    {
      "affs": [
        11
      ],
      "name": "Felix H. Schacher"
    },
    {
      "affs": [
        12
      ],
      "name": "Benjamin Dietzek-Ivanšić"
    },
    {
      "affs": [
        13
      ],
      "name": "Radim Beranek",
      "orcid": "0000-0002-7926-0774"
    },
    {
      "affs": [
        14
      ],
      "name": "Martin Oschatz"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8gtnf1ewbw9s0.bib",
  "cited_by": 1,
  "doi": "10.26434/chemrxiv.15008563/v1",
  "fulltext_url": null,
  "id": "8gtnf1ewbw9s0",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008563/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|Advanced Photocatalysis Techniques"
    ]
  ],
  "openalex": "W7212046024",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15008563/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-09",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/8gtnf1ewbw9s0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:19Z",
      "native_id": "10.26434/chemrxiv.15008563",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008563/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "source:chemrxiv",
      "subfield": "general"
    }
  ],
  "title": "Morphology-Dependent Excited-State Dynamics in Hollow Sphere Poly(Heptazine Imide) Photocatalysts",
  "title_text": "Morphology-Dependent Excited-State Dynamics in Hollow Sphere Poly(Heptazine Imide) Photocatalysts",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:19Z",
  "url": "https://research.draconitic.com/paper/8gtnf1ewbw9s0",
  "venue": "ChemRxiv",
  "versions": []
}