Nanoceria

Subtopics

• (i) Atomic Processes on Ceria Nanoparticle Surfaces
  In a nutshell: Aberration corrected HRTEM is used to observe atomic structures and surface reconstructions on selected ceria nanoparticle facets. In particular {100} type facets are found to show instability resulting in dynamic atomic hopping processes, tracked and recorded by insitu time-series. The Ce-hopping processes are evaluated at various particle sizes, and surface-indices, including corner regions. Reversible hopping is distinguished from reconstructive displacements. The influence of electron radiation and oxygen loss along with the polarity and non-stoichiometry of ceria surfaces are discussed and the impact on predicting catalytic activities is pointed out
  
  Publications:
  “Dynamics of Polar Surfaces on Ceria Nanoparticles Observed In-Situ with Single Atom Resolution”, Advanced Functional Materials 11 (2011) ; ACS Nano 6(1) 421 (2012)

• (ii) Morphology and Microstructure of Ceria Nanostructures
  In a nutshell: HRTEM imaging, electron tomography, and EELS spectroscopy are used to characterise shape, surface facet distribution, cerium oxidation state and internal defects of ceria nanostructures, including octahedral, cuboid, and rod shaped particles. Heating and/or Irradiation are found to produce internal voids of accumulated vacancies with a shape of “negative” nanoparticles inside nanorods. The shape selectivity and defect control are considered essential for tuning catalytic efficiency of those ceria nanostructures
  
  Publications:
  J Phys Chem C 117 24561-24569 (2013);
  Nanoscale 5 6063-6073 (2013)
  Chemistry of Materials 24(10) 1811-1821 (2012)
  Nanoscale 7 5169-5177 (2015)

• (iii) Irradiation of Ceria Nanostructures
  In a nutshell: Ceria and related fluorite-structured oxides are known to be one the most irradiation-resistant materials, including e.g. UO2. Robustness of the cubic-ionic structure, along with capability to accommodate defects or non-stoichiometry, and high oxygen-mobility contribute to tolerance or self-healing property. Electron irradiation of nanoparticulate ceria is performed to complement established bulk-ceria studies with ion or gamma-irradiation. Local amorphisation, lattice swelling, recrystallization, and surface fluidity are amongst the observations, while it is confirmed that exceptional resistance against focused-beam hole drilling applies.
  
  Publications: MRS Proceedings, 1552 (2013), DOI: http://dx.doi.org/10.1557/opl.2013.714