Nanomaterials (Sep 2022)

Structure and Surface Relaxation of CeO<sub>2</sub> Nanoparticles Unveiled by Combining Real and Reciprocal Space Total Scattering Analysis

  • Marco Scavini,
  • Federica Bertolotti,
  • Jonadri Mlloja,
  • Filippo Umbri,
  • Anna Bosc,
  • Serena Cappelli,
  • Stefano Checchia,
  • Cesare Oliva,
  • Patrizia Fumagalli,
  • Davide Ceresoli,
  • Mariangela Longhi,
  • Antonietta Guagliardi,
  • Mauro Coduri

Journal volume & issue
Vol. 12, no. 19
p. 3385


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We present a combined real and reciprocal space structural and microstructural characterization of CeO2 nanoparticles (NPs) exhibiting different crystallite sizes; ~3 nm CeO2 NPs were produced by an inverse micellae wet synthetic path and then annealed at different temperatures. X-ray total scattering data were analyzed by combining real-space-based Pair Distribution Function analysis and the reciprocal-space-based Debye Scattering Equation method with atomistic models. Subtle atomic-scale relaxations occur at the nanocrystal surface. The structural analysis was corroborated by ab initio DFT and force field calculations; micro-Raman and electron spin resonance added important insights to the NPs’ defective structure. The combination of the above techniques suggests a core-shell like structure of ultrasmall NPs. These exhibit an expanded outer shell having a defective fluorite structure, while the inner shell is similar to the bulk structure. The presence of partially reduced O2−δ species testifies to the high surface activity of the NPs. On increasing the annealing temperature, the particle dimensions increase, limiting disorder as a consequence of the progressive surface-to-volume ratio reduction.