Equilibrium shape and surface termination of supported magnetite nanoparticles

Journal
Communications chemistry  
Volume
9
Issue
1
Article Number
158
Citation
Communications Chemistry 9 (1): 158 (2026)
Publisher DOI
10.1038/s42004-026-02008-4
Scopus ID
2-s2.0-105036201048
Publisher
Nature Research
The equilibrium shape and surface termination of magnetite nanoparticles (NPs) are fundamental properties that determine the physical and chemical properties of the supercrystal structure of oleic acid-coated magnetite NPs. Here, we studied the equilibrium shape of magnetite (Fe3O4) NPs supported by Al2O3(0001) single-crystalline surfaces. We report the growth of epitaxial (111)-oriented NPs exhibiting a triangular shape with a height-to-diameter aspect ratio of 0.42 over a wide growth temperature range. We probed the surface termination of the NP facets by adsorbing formic acid as a prototypical molecule representing the adsorption behavior of oleic acid. We identified infrared absorption bands characteristic of dissociative adsorption on (111) facets with the iron tetrahedral (Fetet1) termination, as well as on mixed-terminated (100) side facets. Our experimental findings are supported by predictions of the NP shape using surface-free energy calculations from ab initio thermodynamics. The experimentally observed nanoparticle shape can only be rationalized by the presence of bulk-terminated {100} type facets. Such a fundamental understanding of the shape and surface terminations of oxide nanoparticles is crucial for tailoring the properties of hybrid hierarchical materials and drug carriers and for their development.
DDC Class
620.11: Engineering Materials
620.5: Nanotechnology
530.41: Mechanics of Solids
Lizenz
https://creativecommons.org/licenses/by/4.0/
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