# Strongly Bound Surface Water Affects the Shape Evolution of Cerium Oxide Nanoparticles

Symington, Adam R., Molinari, Marco, Moxon, Samuel, Flitcroft, Joseph M., Sayle, Dean C., Parker, Stephen C. (2020) Strongly Bound Surface Water Affects the Shape Evolution of Cerium Oxide Nanoparticles. The Journal of Physical Chemistry C, 124 (6). pp. 3577-3588. ISSN 1932-7447. E-ISSN 1932-7455. (doi:10.1021/acs.jpcc.9b09046) (KAR id:80395)

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## Abstract

The surface structure and composition of functional materials are well-known to be critically important factors controlling the surface reactivity. However, when doped the surface composition will change, and the challenge is to identify its impact on important surface processes and nanoparticle morphologies. We have begun to address this by using a combination of density functional theory and potential-based methods to investigate the effect of surface dopants on water adsorption and morphology of the technologically important material, CeO$$_2$$, which finds application as electrolyte in SOFCs, catalyst in soot combustion, and enzyme mimetic agents in biomedicine. We show that by mapping CeO$$_2$$ surface phase diagrams we can predict nanoparticle morphologies as a function of dopant, temperature, and water partial pressure. Our results show that low-temperature, undoped CeO$$_2$$ nanocubes with active {100} surface sites are thermodynamically stable, but at the typical high temperature, operating conditions favor polyhedra where {100} surfaces are replaced by less active {111} surfaces by surface ion migration. However, doping with trivalent cations, such as Gd$$^{3+}$$, will increase binding of water on the {100} surfaces and hence act to preserve the cuboidal architecture by capping the active surfaces. As surfaces tend to be decorated by impurities and dopants it is clear that their role should receive more attention and the approach we describe can be routinely applied to nanomaterials, morphologies, and associated active/inactive surfaces.

Item Type: Article 10.1021/acs.jpcc.9b09046 Impurities, Oxides, Adsorption, Nanoparticles, Surface energy Q Science > QD Chemistry Divisions > Division of Natural Sciences > School of Physical Sciences Dean Sayle 07 Mar 2020 08:54 UTC 16 Feb 2021 14:11 UTC https://kar.kent.ac.uk/id/eprint/80395 (The current URI for this page, for reference purposes) https://orcid.org/0000-0001-7227-9010