Hexagonal single-crystalline cerium carbonate hydroxide(CeCO_3OH) precursors with dendrite morphologies have been synthesized by a facile hydrothermal method at 180℃ using CeCl_3-7H_2O as the cerium source,triethylenetetramine as both an alkaline and carbon source,with triethylenetetramine also playing an important role in the formation of the dendrite structure.Polycrystalline ceria(CeO_2) have been obtained by calcining the precursor at 500 ℃ for 4 h.The morphology of the precursor was partly maintained during the heating process.The optical absorption spectra indicate the CeO_2nano/microstructures have a direct band gap of 2.92 eV,which is lower than values of the bulk powder due to the quantum size effect.The high absorption in the UV region for CeO_2 nano/microstructure indicated that this material was expected to be used as UV-blocking materials.
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