Effects of dopant concentration and calcination temperature on the microstructure of Ca-doped ceria nanopowders

We demonstrate a systematic investigation on the microstructure of the Ca-doped ceria affected by different dopant concentrations and calcination temperatures. It has been shown that nanopowders of Ca-doped ceria have been successfully prepared in a broad dopant concentration region from 5 at.% to 70 at.%. By using various microstructure analysis techniques, the secondary phase has been determined, and the solubility of Ca in ceria has been realized to be less than 20 at.%. It has been also found that the calcination temperature greatly affects the grain growth of the calcined powders, and high temperature calcination treatments would cause lattice relaxation and lead to precipitations, based on which proper calcination conditions are suggested.