{
  "abstract": "We present a comprehensive multiscale theoretical framework for the topotactic solid-state thermolysis of ZrOCl2·8H2O and NaHCO3 (1:2 molar ratio) to metastable tetragonal zirconia (t-ZrO2). Six quantitatively coupled sub-models are developed and validated against experimental data [1]: (i) a thermodynamic Hess-cycle analysis yielding ΔG°topo = −287 ± 18 kJ mol-1 per Zr at 400 °C, which is 56 ± 28 kJ mol-1 more negative than the sol–gel benchmark; (ii) a surface-energy crystallite stability model predicting a critical size Dcr = 13.5 ± 2.0 nm at 400 °C, consistent with the experimentally observed coherent scattering region (CSR) of 11.3 nm; (iii) an oxygen-vacancy thermodynamic model with ΔGvacancy = −3.7 to −36.8 kJ mol-1 for O/Zr = 1.63–1.98, rationalising the uniquely reductive micro-atmosphere of the solid-state route; (iv) a gas-wedge fragmentation model with ℱ = 2.07–4.17, confirming primary particle breakdown to 40–80 nm prior to t-ZrO2 crystallisation; (v) a JMAK kinetic analysis of the t → m transformation giving Ea = 81 ± 6 kJ mol-1 and Avrami exponent n = 0.27–0.31, consistent with defect-driven surface nucleation; and (vi) a grain-growth model with Q = 185 ± 15 kJ mol-1 in the presence of NaCl, representing a 25–40 kJ mol-1 reduction compared to NaCl-free systems. A (D, x)-phase stability map predicts a re-entrant t → amorphous boundary at O/Zr < 1.60 for D < 5 nm — a novel, falsifiable prediction — and quantitatively reproduces all experimental phase fields from ref. [1]. The by-product NaCl acts as a dual-role flux, stabilising t-ZrO2 nanoparticles below 500 °C via grain-boundary pinning but accelerating grain coarsening and the t → m transition above 600 °C. Optimal synthesis conditions are established: 1:2 molar ratio, heating rate β = 8–12 °C min-1, calcination at 350–450 °C, and post-synthesis drying at 55–65% relative humidity.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": null,
  "author_total": 1,
  "authors": [
    {
      "name": "Володимир Трихліб",
      "orcid": "0009-0002-6422-759X"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/91efgyk04d4np.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15009693/v1",
  "fulltext_url": null,
  "id": "91efgyk04d4np",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009693/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",
      "2505|Thermal and Kinetic Analysis"
    ]
  ],
  "openalex": "W7214995354",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15009693/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-30",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/91efgyk04d4np.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:21Z",
      "native_id": "10.26434/chemrxiv.15009693",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009693/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2505|Thermal and Kinetic Analysis",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Synthesis of metastable t-ZrO2 via solid-state thermolysis of ZrOCl2·8H2O/NaHCO3: thermodynamics, oxygen vacancies, grain growth and phase stability",
  "title_text": "Synthesis of metastable t-ZrO2 via solid-state thermolysis of ZrOCl2·8H2O/NaHCO3: thermodynamics, oxygen vacancies, grain growth and phase stability",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:21Z",
  "url": "https://research.draconitic.com/paper/91efgyk04d4np",
  "venue": "ChemRxiv",
  "versions": []
}