The lattice parameter of nanocrystalline ceria films prepared by sputtering was monitored as a function of annealing temperature. Within the temperature range of 150-420 degrees C, an equilibrium with atmospheric oxygen is established within a few hours, whereas grain growth does not occur. On the basis of the experimental results and analysis of literature data, we present a model that posits the formation of a non-uniform grain structure with stoichiometric interiors and oxygen deficient boundaries. This model, based on defect thermodynamics, correctly describes the dependence of the lattice parameter of nanocrystalline ceria on annealing temperature and grain size and can be extended to other materials as well.
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http://dx.doi.org/10.1039/b513764k | DOI Listing |
J Phys Chem C Nanomater Interfaces
October 2024
Department of Physical and Life Sciences, University of Huddersfield, Queensgate, Huddersfield HD1 3DH, U.K.
Nanocrystalline ceria exhibits significant redox activity and oxygen storage capacity. Any factor affecting its morphology can tune such activities. Strain is a promising method for controlling particle morphology, whether as core@shell structures, supported nanoparticles, or nanograins in nanocrystalline ceria.
View Article and Find Full Text PDFDalton Trans
October 2024
Talent Development Centre, Indian Institute of Science Challakere Campus at Kudapura, Chitradurga, Karnataka 577536, India.
Fluorite-type nanocrystalline 5% iron-substituted ceria (CeFeO) was synthesized by the solution combustion method with an average crystallite size of 15 nm. The catalyst was well characterized by SEM, EDX, XPS, XRD, and H-TPR studies, which confirmed the substitution of Fe in the CeO lattice. This precious metal-free catalyst was developed for the selective conversion of various arylboronic acids to the corresponding biphenyls and phenols employing KSO and HO, respectively.
View Article and Find Full Text PDFMaterials (Basel)
August 2024
School of Chemistry and Chemical Engineering, Faculty of Engineering & Physical Sciences, University of Surrey, Guildford GU2 7XH, UK.
The necessity for high operational temperatures presents a considerable obstacle to the commercial viability of solid oxide fuel cells (SOFCs). The introduction of active co-dopant ions to polycrystalline solid structures can directly impact the physiochemical and electrical properties of the resulting composites including crystallite size, lattice parameters, ionic and electronic conductivity, sinterability, and mechanical strength. This study proposes cobalt-iron-substituted gadolinium-doped ceria (CoFeGDC) as an innovative, nickel-free anode composite for developing ceramic fuel cells.
View Article and Find Full Text PDFCrystalline cerium(III) phosphate (CePO), cerium(IV) phosphates, and nanocrystalline ceria are considered to be promising components of sunscreen cosmetics. This paper reports on a study in which, for the first time, a quantitative comparative analysis was performed of the UV-shielding properties of CePO, Ce(PO)(HPO)(HO), and CePO/CeO composites. Both the sun protection factor and protection factor against UV-A radiation of the materials were determined.
View Article and Find Full Text PDFACS Catal
July 2023
Department of Chemistry and NIS Centre, University of Turin, Via Giuria 7, 10125 Turin, Italy.
In this work, we have synthesized through an efficient electrostatic deposition a Pt single-atom catalyst (SAC) supported on a Ce-MOF. The basic solution employed in the impregnation process favors the deprotonation of the hydroxyl groups allocated on the clusters that can easily interact with the cationic Pt species. The resulting material, denoted as Pt/UiO-66(Ce), shows an increment of Ce content, as demonstrated by UV-vis and Ce L-edge XANES spectroscopy.
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