Combustion Synthesis and Characterization of CeO₂ Nanopowder

Bojana Šećerov,^a Željka Andrić,^a Nadica Abazović,^a,b Radenka Krsmanović,^a Miodrag Mitrić,^a Amelia Montonea and Miroslav D. Dramićanina*

^a Institute of Nuclear Sciencies “Vinča,” P.O. Box 522, 11000 Beograd, Serbia
^b ENEA, Unità Materiali e Nuove Tecnologie, CR Casaccia - C.P. 2400, 00100 Roma AD
* Corresponding author: E-mail: dramican@vin.bg.ac.yu

Abstract
Modified combustion procedure, named as polymer complex solution method (PCS), was used for synthesis of CeO₂ nanopowder. As fuel was employed polyethylene glycol (PEG) with average molecular weight 200. Post-synthesis thermal treatments were done at 800 °C for 2 hours. X-ray powder diffraction, electron microscopy (SEM and TEM), laser light scattering, infrared spectroscopy, UV-VIS diffuse reflectance spectroscopy and luminescence spectroscopy were used as characterization methods. The objectives were to investigate the structure and morphology of the synthesized powder, in particular the aggregation and particle size distribution, and its luminescence properties. Photoluminescent properties of CeO₂ nanopowder were determined from its emission and excitation spectra. In the excitation spectra two lines were present: one at 322 nm and other at 356 nm. Two lines were also visible in the emission spectra, one at 427 nm and other at 492 nm. Violet emission placed at 427 nm and excitation at 356 nm corresponded to 5D1→4F1 transition of cerium trivalent ion. A UV-VIS diffuse reflectance spectrum shows the absorption edge at 375 nm. The observed spectral blue shift revealed the presence of fine crystallites which escape XRD detection. The presented results demonstrate that this simple preparation technique provides well crystallized nanoparticles of CeO₂.

Keywords: Combustion synthesis, ceria, optical spectroscopy, nanopowder, luminescence.