Hydrothermal Synthesis and Microstructural Characteristics of Rare Earth Titanates
稀土钛酸盐复合氧化物的水热合成和微结构特征研究

Hydrothermally synthesized ReNaTi2O6(Re=Ce, Nd and Eu) were characterized by means of XRD, SEM, XPS and 151Eu Mossbauer spectroscopy. The results show that the crystallization conditions e.g., the mineralizer, initial molar concentration and so on determine the structural types and the purity of the resulting products. During the hydrothermal crystallization, sodium ions may occupy the perovskite lattice but do not result in the reduction of Ti(IV) to lower valence state. The binding energy for the main peak of Ce3d5/2 in CeNaTi2O6 is 885.45eV, suggesting that the cerium ions exist mainly as Ce(III). NdNaTi2O6 has regular grain shape. For EuNaTi2O6, the contribution from the lattice field is larger than that of second 4f. The products from hydrothermal conditions have lower defect concentration and smaller lattice distortion.