Nanoceria synthesis in the KCl‐LiCl salt system: Crystal formation and properties

Nanoceria is an important function material and is widely used in catalytic applications due to its excellent redox properties. Here, we report a simple method to synthesize uniform polyhedral nanoceria powder by the KCl‐LiCl molten salt method. TEM micrographs of the product showed that polyhedral nanoceria particles of 30 nm average size were obtained from cerium carbonate hydroxide when treated at 600°C for 4 hours. Results indicated that the crystal structure broke down to ceria crystal nuclei in the molten salt system at an elevated temperature, and the Ce3+ dissolved in the KCl‐LiCl molten salts provided a cerium source for crystal growth. The crystal and particle sizes increased with treatment temperature. UV‐visible absorption results showed that this nanoceria powder had a significant red shift, and its narrow band gap of 2.7 eV suggests a potential application for photocatalysis. The produced nanoceria had a somewhat lower catalytic activity for CO oxidization than commercial nanoceria, mainly due to smaller specific surface area, but had a higher stability.