Contraction, cation oxidation state and size effects in cerium oxide nanoparticles.

Title Contraction, cation oxidation state and size effects in cerium oxide nanoparticles.
Authors J.Stefano Pe Cresi; M.Chiara Spadaro; S. D'Addato; S. Valeri; L. Amidani; F. Boscherini; G. Bertoni; D. Deiana; P. Luches
Journal Nanotechnology
DOI 10.1088/1361-6528/aa926f
Abstract

An accurate description of the structural and chemical modifications of cerium oxide nanoparticles (NPs) is mandatory for understanding their functionality in applications. In this work we investigate the relation between local atomic structure, oxidation state, defectivity and size in cerium oxide NPs with variable diameter below 10 nm, using x-ray absorption fine structure analysis in the near and extended energy range. The NPs are prepared by physical methods under controlled conditions and analyzed in morphology and crystalline quality by high resolution transmission electron microscopy. We resolve here an important question on the local structure of cerium oxide NPs: we demonstrate a progressive contraction in the Ce-O interatomic distance with decreasing NP diameter and we relate the observed effect to the reduced dimensionality. The contraction is not significantly modified by inducing a 4%-6% higher Ce3+ concentration through thermal annealing in high vacuum. The consequences of the observed average cation-anion distance contraction on the properties of the NPs are discussed.

Citation J.Stefano Pe Cresi; M.Chiara Spadaro; S. D'Addato; S. Valeri; L. Amidani; F. Boscherini; G. Bertoni; D. Deiana; P. Luches.Contraction, cation oxidation state and size effects in cerium oxide nanoparticles.. Nanotechnology. 2017;28(49):495702. doi:10.1088/1361-6528/aa926f

Related Elements

Cerium

See more Cerium products. Cerium (atomic symbol: Ce, atomic number: 58) is a Block F, Group 3, Period 6 element with an atomic weight of 140.116. The number of electrons in each of cerium's shells is 2, 8, 18, 19, 9, 2 and its electron configuration is [Xe]4f2 6s2. Cerium Bohr ModelThe cerium atom has a radius of 182.5 pm and a Van der Waals radius of 235 pm. In its elemental form, cerium has a silvery white appearance. Cerium is the most abundant of the rare earth metals. It is characterized chemically by having two valence states, the +3 cerous and +4 ceric states. The ceric state is the only non-trivalent rare earth ion stable in aqueous solutions. Elemental CeriumIt is therefore strongly acidic and oxidizing, in addition to being moderately toxic.The cerous state closely resembles the other trivalent rare earths. Cerium is found in the minerals allanite, bastnasite, hydroxylbastnasite, monazite, rhabdophane, synchysite and zircon. Cerium was discovered by Martin Heinrich Klaproth, Jöns Jakob Berzelius, and Wilhelm Hisinger in 1803 and first isolated by Carl Gustaf Mosander in 1839. The element was named after the asteroid Ceres, which itself was named after the Roman god of agriculture.

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