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Environment-mediated structure, surface redox activity and reactivity of ceria nanoparticles

Sayle, T.X.T., Molinari, M., Das, S., Bhatta, U.M., Möbus, G., Parker, S.C., Seal, S., Sayle, D.C. (2013) Environment-mediated structure, surface redox activity and reactivity of ceria nanoparticles. Nanoscale, 5 (13). pp. 6063-6073. ISSN 2040-3364. (doi:10.1039/c3nr00917c)

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https://doi.org/10.1039/c3nr00917c

Abstract

Nanomaterials, with potential application as bio-medicinal agents, exploit the chemical properties of a solid, with the ability to be transported (like a molecule) to a variety of bodily compartments. However, the chemical environment can change significantly the structure and hence properties of a nanomaterial. Accordingly, its surface reactivity is critically dependent upon the nature of the (biological) environment in which it resides. Here, we use Molecular Dynamics (MD) simulation, Density Functional Theory (DFT) and aberration corrected TEM to predict and rationalise differences in structure and hence surface reactivity of ceria nanoparticles in different environments. In particular we calculate reactivity 'fingerprints' for unreduced and reduced ceria nanoparticles immersed in water and in vacuum. Our simulations predict higher activities of ceria nanoparticles, towards oxygen release, when immersed in water because the water quenches the coordinative unsaturation of surface ions. Conversely, in vacuum, surface ions relax into the body of the nanoparticle to relieve coordinative unsaturation, which increases the energy barriers associated with oxygen release. Our simulations also reveal that reduced ceria nanoparticles are more active towards surface oxygen release compared to unreduced nanoceria. In parallel, experiment is used to explore the activities of ceria nanoparticles that have suffered a change in environment. In particular, we compare the ability of ceria nanoparticles, in an aqueous environment, to scavenge superoxide radicals compared to the same batch of nanoparticles, which have first been dried and then rehydrated. The latter show a distinct reduction in activity, which we correlate to a change in the redox chemistry associated with moving between different environments. The reactivity of ceria nanoparticles is therefore not only environment dependent, but is also influenced by the transport pathway or history required to reach the particular environment in which its reactivity is to be exploited. © 2013 The Royal Society of Chemistry.

Item Type: Article
DOI/Identification number: 10.1039/c3nr00917c
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - Nanoscale [Field not mapped to EPrints] C2 - 23719690 [Field not mapped to EPrints] AD - Department of Engineering and Applied Science, Cranfield University, Defence Academy of the United Kingdom, Shrivenham SN6 8LA, United Kingdom [Field not mapped to EPrints] AD - Department of Chemistry, University of Bath, Claverton Down, Bath Avon BA2 7AY, United Kingdom [Field not mapped to EPrints] AD - Department of Mechanical, Materials and Aerospace Engineering, Advanced Materials Processing Analysis Center, University of Central Florida, Orlando, FL, United States [Field not mapped to EPrints] AD - NanoLAB Centre, Department of Materials Science and Engineering, Sheffield University, Sheffield S1 3JD, United Kingdom [Field not mapped to EPrints] AD - School of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NZ, United Kingdom [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled keywords: Aberration corrected TEM, Aqueous environment, Ceria nanoparticles, Chemical environment, Coordinative unsaturations, Molecular dynamics simulations, Superoxide radical, Surface reactivity, Molecular dynamics, Nanostructured materials, Oxygen, Redox reactions, Vacuum, Nanoparticles, cerium, metal nanoparticle, oxygen, scavenger, superoxide, water, animal, article, chemistry, human, molecular dynamics, oxidation reduction reaction, Animals, Cerium, Free Radical Scavengers, Humans, Metal Nanoparticles, Molecular Dynamics Simulation, Oxidation-Reduction, Oxygen, Superoxides, Water
Subjects: Q Science > QD Chemistry
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Dean Sayle
Date Deposited: 27 Jan 2015 16:22 UTC
Last Modified: 29 May 2019 14:06 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/46771 (The current URI for this page, for reference purposes)
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