Crystallization Mechanism of Gel-Derived SiO2-TiO2 Amorphous Nanobeads Elucidated by High-Temperature In Situ Experiments

Zandonà A, Véron E, Helsch G, Canizarès A, Deubener J, Allix M, Genevois C (2023)

Publication Type: Journal article

Publication year: 2023

Journal

Crystal Growth and Design American Chemical Society

DOI: 10.1021/acs.cgd.3c00300

Abstract

SiO2-TiO2 amorphous nanobeads with a TiO2 content up to 50 mol % were synthesized by sol-gel spray drying. Their crystallization during heat treatments was then characterized by in situ high-temperature techniques including X-ray diffraction, Raman spectroscopy, and particularly high-resolution transmission electron microscopy. Intrinsic nanoscale chemical modulations could be identified already in the as-prepared nanobeads and were shown to play a major role for the nonisochemical precipitation of TiO2 nanocrystals during heating experiments: the size and compositional contrast of such fluctuations progressively evolved and increased until the emergence of long-range ordering. The formation of TiO2 polymorphs occurred according to Ostwald’s rule of stages, with the metastable TiO2(B) phase acting as a precursor to stabilize anatase and rutile. The temporary appearance of TiO2(B) nanocrystals at early annealing stages was interpreted as the first direct experimental observation of subcritical crystalline nuclei.

Involved external institutions

National Center for Scientific Research / Centre national de la recherche scientifique (CNRS) FR France (FR) Technische Universität Clausthal / Clausthal University of Technology DE Germany (DE)

How to cite

APA:

Zandonà, A., Véron, E., Helsch, G., Canizarès, A., Deubener, J., Allix, M., & Genevois, C. (2023). Crystallization Mechanism of Gel-Derived SiO2-TiO2 Amorphous Nanobeads Elucidated by High-Temperature In Situ Experiments. Crystal Growth and Design. https://dx.doi.org/10.1021/acs.cgd.3c00300

MLA:

Zandonà, Alessio, et al. "Crystallization Mechanism of Gel-Derived SiO2-TiO2 Amorphous Nanobeads Elucidated by High-Temperature In Situ Experiments." Crystal Growth and Design (2023).

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