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

Thi X.T. Sayle, Marco Molinari, Soumen Das, Umananda M. Bhatta, Günter Möbus, Stephen C. Parker, Sudipta Seal, Dean C. Sayle

Research output: Contribution to journalArticle

32 Citations (Scopus)

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.

LanguageEnglish
Pages6063-6073
Number of pages11
JournalNanoscale
Volume5
Issue number13
DOIs
Publication statusPublished - 5 Jul 2013
Externally publishedYes

Fingerprint

Cerium compounds
Nanoparticles
Oxygen
Nanostructured materials
Water
Vacuum
Ions
Oxidation-Reduction
Energy barriers
Aberrations
Superoxides
Chemical properties
Density functional theory
Molecular dynamics
Transmission electron microscopy
Molecules
Computer simulation

Cite this

Sayle, T. X. T., Molinari, M., Das, S., Bhatta, U. M., Möbus, G., Parker, S. C., ... Sayle, D. C. (2013). Environment-mediated structure, surface redox activity and reactivity of ceria nanoparticles. Nanoscale, 5(13), 6063-6073. https://doi.org/10.1039/c3nr00917c
Sayle, Thi X.T. ; Molinari, Marco ; Das, Soumen ; Bhatta, Umananda M. ; Möbus, Günter ; Parker, Stephen C. ; Seal, Sudipta ; Sayle, Dean C. / Environment-mediated structure, surface redox activity and reactivity of ceria nanoparticles. In: Nanoscale. 2013 ; Vol. 5, No. 13. pp. 6063-6073.
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Sayle, TXT, Molinari, M, Das, S, Bhatta, UM, Möbus, G, Parker, SC, Seal, S & Sayle, DC 2013, 'Environment-mediated structure, surface redox activity and reactivity of ceria nanoparticles', Nanoscale, vol. 5, no. 13, pp. 6063-6073. https://doi.org/10.1039/c3nr00917c

Environment-mediated structure, surface redox activity and reactivity of ceria nanoparticles. / Sayle, Thi X.T.; Molinari, Marco; Das, Soumen; Bhatta, Umananda M.; Möbus, Günter; Parker, Stephen C.; Seal, Sudipta; Sayle, Dean C.

In: Nanoscale, Vol. 5, No. 13, 05.07.2013, p. 6063-6073.

Research output: Contribution to journalArticle

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AU - Sayle, Thi X.T.

AU - Molinari, Marco

AU - Das, Soumen

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AU - Möbus, Günter

AU - Parker, Stephen C.

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