Ligand induced shape transformation of thorium dioxide nanocrystals
Nanocrystals (NCs) with size and shape dependent properties are a thriving research field. Significant progress has been made in the controlled synthesis of NCs of stable elements in the past two decades; however, the knowledge of the NCs of actinide compounds has been considerably limited due the difficulties in handling them both experimentally and theoretically. Actinide compounds, especially actinide oxides, play a critical role in many stages of the nuclear fuel cycle. Recently, a non-aqueous surfactant assisted approach has been developed for the synthesis of actinide oxide NCs with different morphologies, but an understanding of its control factors is still missing to date. Herein we present a comprehensive study on the low index surfaces of thorium dioxide (ThO2) and their interactions with relevant surfactant ligands using density functional calculations. A systematic picture on the thermodynamic stability of ThO2 NCs of different sizes and shapes is obtained employing empirical models based on the calculated surface energies. It is found that bare ThO2 NCs prefer the octahedral shape terminated by (111) surfaces. Oleic acid displays selective adsorption on the (110) surface, leading to the shape transformation from octahedrons to nanorods. Other ligands such as acetylacetone, oleylamine, and trioctylphosphine oxide do not modify the equilibrium shape of ThO2 NCs. This research provides atomic level insights into the anisotropic growth of ThO2 NCs that was recently observed in experiments, and thus may contribute to the controlled synthesis of actinide oxide NCs with well-defined size and shape for future applications.
- Research Organization:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division; USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- 89233218CNA000001; AC52-06NA25396
- OSTI ID:
- 1524386
- Alternate ID(s):
- OSTI ID: 1434968
- Report Number(s):
- LA-UR--17-31042
- Journal Information:
- Physical Chemistry Chemical Physics. PCCP, Journal Name: Physical Chemistry Chemical Physics. PCCP Journal Issue: 26 Vol. 20; ISSN 1463-9076; ISSN PPCPFQ
- Publisher:
- Royal Society of ChemistryCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Structural properties of ultra-small thorium and uranium dioxide nanoparticles embedded in a covalent organic framework
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journal | January 2020 |
Understanding the size effects on the electronic structure of ThO 2 nanoparticles
|
journal | January 2019 |
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