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Size Dependence of Lattice Parameter and Electronic Structure in CeO2 Nanoparticles
journal contribution
posted on 2020-04-01, 19:12 authored by Damien Prieur, Walter Bonani, Karin Popa, Olaf Walter, Kyle W. Kriegsman, Mark H. Engelhard, Xiaofeng Guo, Rachel Eloirdi, Thomas Gouder, Aaron Beck, Tonya Vitova, Andreas C. Scheinost, Kristina Kvashnina, Philippe MartinIntrinsic properties
of a compound (e.g., electronic structure, crystallographic structure,
optical and magnetic properties) define notably its chemical and physical
behavior. In the case of nanomaterials, these fundamental properties
depend on the occurrence of quantum mechanical size effects and on
the considerable increase of the surface to bulk ratio. Here, we explore
the size dependence of both crystal and electronic properties of CeO2 nanoparticles (NPs) with different sizes by state-of-the
art spectroscopic techniques. X-ray diffraction, X-ray photoelectron
spectroscopy, and high-energy resolution fluorescence-detection hard
X-ray absorption near-edge structure (HERFD-XANES) spectroscopy demonstrate
that the as-synthesized NPs crystallize in the fluorite structure
and they are predominantly composed of CeIV ions. The strong
dependence of the lattice parameter with the NPs size was attributed
to the presence of adsorbed species at the NPs surface thanks to Fourier
transform infrared spectroscopy and thermogravimetric analysis measurements.
In addition, the size dependence of the t2g states in the
Ce LIII XANES spectra was experimentally observed by HERFD-XANES
and confirmed by theoretical calculations.