Title: Ligand induced shape transformation of thorium dioxide nanocrystals

Abstract

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 modifymore » 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.« less

Authors:

Wang, Gaoxue  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-4812-7257"
• Search orcid.org for ORCID "0000-0003-4812-7257"

Batista, Enrique R.  ^[1];

• Search DOE PAGES for author "Batista, Enrique R."
• Search DOE PAGES for ORCID "0000-0002-3074-4022"
• Search orcid.org for ORCID "0000-0002-3074-4022"

Yang, Ping  ^[1]

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• Search DOE PAGES for ORCID "0000-0003-4726-2860"
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+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:

2018-04-09

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division; USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1524386

Alternate Identifier(s):

OSTI ID: 1434968

Report Number(s):

LA-UR-17-31042
Journal ID: ISSN 1463-9076; PPCPFQ

Grant/Contract Number:  

89233218CNA000001; AC52-06NA25396

Resource Type:

Accepted Manuscript

Journal Name:

Physical Chemistry Chemical Physics. PCCP (Print)

Additional Journal Information:

Journal Name: Physical Chemistry Chemical Physics. PCCP (Print); Journal Volume: 20; Journal Issue: 26; Journal ID: ISSN 1463-9076

Publisher:

Royal Society of Chemistry

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY