Hydrothermal Crystallization and Crystal Growth of Un-doped and ZrO₂ -doped CeO₂

Abstract

The crystallization of un-doped and ZrO₂-doped CeO₂ was studied from the precipitated hydrous ceria with KF, LiCl, LiBr, K₂CO₃, LiNO₃, Li₂S0₄ and NaOH solutions under 100 MPa at 500 to 600°C for 24 h. The KF and Li₂SO₄ solutions enhanced effectively the growth of the crystallite of un-doped CeO₂. The LiCl, LiBr and Li₂SO₄ solutions, whereas, enhanced the growth of the crystallite of ZrO₂-doped CeO₂. The calcination of the precipitated hydrous ceria contributed to the hydrothermal growth of the crystallite of ZrO₂-doped CeO₂ with LiCl solution. The single crystals of un-doped CeO₂ (120µm) and ZrO₂-doped CeO₂ (200µm) were obtained by the hydrothermal treatments with KF and LiCl solutions, respectively.