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Updated: Jul 10, 2025
08:43
Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles
Published on: October 27, 2018
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Composition and Electronic Structure of La2O3/CNFs@C Core-Shell Nanoparticles with Variable Oxygen Content.
Evgeniya V Suslova1, Alexander N Ulyanov1, Alexey P Kozlov1
1Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
Nanomaterials (Basel, Switzerland)
|November 24, 2023
Summary
Lanthanum oxide (La₂O₃) nanoparticles on carbon nanoflakes (CNFs) were oxidized, increasing La₂O₃ content and altering electronic structures. This study reveals the link between material composition and electron paramagnetic resonance (EPR) spectra.
Area of Science:
- Materials Science
- Nanotechnology
- Chemistry
Background:
- Core-shell nanostructures offer unique properties for advanced applications.
- Carbon nanoflakes (CNFs) provide a versatile matrix for stabilizing nanoparticles.
- Oxidation is a key process for tuning material surface chemistry and electronic properties.
Purpose of the Study:
- To synthesize and characterize La₂O₃/CNFs@C core-shell structures.
- To investigate the effects of nitric acid vapor oxidation on the composition and electronic structure of La₂O₃/CNFs@C.
- To establish a correlation between material composition and electron paramagnetic resonance (EPR) spectra.
Main Methods:
- Synthesis of La₂O₃ nanoparticles stabilized on CNF matrix.
- Graphitization to form La₂O₃/CNFs@C core-shell structures.
- Controlled oxidation using nitric acid vapors.
- Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) for composition analysis.
- Electron paramagnetic resonance (EPR) spectroscopy for electronic structure assessment.
Main Results:
- Oxidation increased the oxygen and La₂O₃ content in La₂O₃/CNFs@C_x samples with oxidation duration.
- Two types of paramagnetic centers (localized and mobile electrons) were detected in all samples.
- The ratio of sp² to sp³ hybridized carbon atoms, oxygen-containing groups, and coordinated La atoms influenced the EPR spectra.
Conclusions:
- Nitric acid vapor oxidation effectively modifies the surface composition and electronic properties of La₂O₃/CNFs@C.
- A novel correlation between the bulk/surface composition and the EPR spectra of these nanomaterials was established.
- The findings provide insights into tailoring nanomaterial properties for specific applications through controlled oxidation.
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