Effect of Rare Earth Dopants on Structural Characteristics of Nanoceria Synthesized by Combustion Method

Abstract

Rare earth (RE)-doped ceria powders with a chemical composition of Ce1 − xRExO2 − x / 2 (X: 0.1 and RE: Gd, Sm, Er, Pr, Nd and Y) were prepared by nitrate-fuel combustion method. The TG and DT analyses of the as-synthesized powders showed a complete combustion with a small range endothermic process within a broad exothermic reaction. GDC, SDC, EDC, PDC, NDC and YDC precursors were calcined at 700 °C for 2 h and characterized using XRD, SEM and TEM. Powder characteristics such as morphology, crystallite size, primary particle size, lattice parameter and lattice strain of calcined powders have been studied. All X-ray diffraction patterns of as-synthesized and calcined samples were indexed as fluorite structure. The crystallite size of nanoceria obtained by Scherrer's formula was between 17 and 19.5 nm and via Williamson–Hall (W–H) plots in the range of 25–38 nm that shows the effect of lattice strain on the average crystallite size. Primary particle size calculated from BET data was in the range of 24–37 nm. TEM images showed fine spherical particles and SAED patterns confirmed fluorite structure of all powders.