Size Dependence of Lattice Parameter and Electronic Structure in CeO2 Nanoparticles

Damien Prieur (1, 2) , Walter Bonani (3) , Karin Popa (3) , Olaf Walter (3) , Kyle W. Kriegsman (4) , Mark H. Engelhard (5) , Xiaofeng Guo (4) , Rachel Eloirdi (3) , Thomas Gouder (3) , Aaron Beck (6) , Tonya Vitova (6) , Andreas Scheinost (7, 1) , Kristina Kvashnina (7, 1) , Philippe Martin (8)

1 ESRF - European Synchrotron Radiation Facility [Grenoble]
2 HZDR - Helmholtz-Zentrum Dresden-Rossendorf
3 JRC - European Commission - Joint Research Centre [Karlsruhe]
4 WSU - Washington State University
5 EMSL - William R. Wiley Environmental Molecular Sciences Laboratory
6 Institute for Nuclear Waste Disposal
7 IRE - Institute of Resource Ecology [Dresden]
8 DMRC - Département de recherche sur les procédés pour la mine et le recyclage du combustible

Intrinsic 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. However, the literature on this size-dependence and on the involved mechanisms is quite elusive and scarce. 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. XRD, XPS and HERFD-XANES 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 FTIR and TGA measurements. In addition, the size-dependence of the t2g level in the Ce LIII XANES spectra was experimentally observed by HERFD-XANES and confirmed by theoretical calculations.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Damien Prieur, Walter Bonani, Karin Popa, Olaf Walter, Kyle W. Kriegsman, et al.. Size Dependence of Lattice Parameter and Electronic Structure in CeO2 Nanoparticles. Inorganic Chemistry, 2020, 59 (8), pp.5760-5767. ⟨10.1021/acs.inorgchem.0c00506⟩. ⟨cea-03593552⟩