Effect of copper on thermal stability of nanocrystalline ceria

Abstract

Cerium (IV) oxide (CeO₂) is extensively used as a catalyst because it has numerous advantages over conventional catalysts, like low cost, better poisoning resistance, high catalytic activity due to the facile Ce⁴⁺ / Ce³⁺ redox reaction and high oxygen storage capacity. CeO₂ nanoparticles have higher specific surface area and better redox properties, and thus an increased catalytic activity in comparison to bulk materials. However, at elevated temperatures ceria nanoparticles are very prone to coarsening. In order to increase the thermal stability of CeO₂ nanoparticles, but also improve its catalytic properties, metal ions are incorporated into the CeO₂ crystal structure. The aim of this study was to compare coarsening kinetics of nanocrystalline CeO₂ and nanocrystalline CeO₂ doped with 10 mol. % of copper in order to determine the effect of doping on thermal stability. Samples were prepared by hydrothermal synthesis and thermally treated at different temperatures and processing times. The samples were analyzed by X-ray diffraction analysis and the crystallite sizes were calculated using the Scherrer’s equation. Based on the obtained crystallite sizes, kinetic parameters were determined and it was found that copper addition has a positive effect on the thermal stability of CeO₂.