纳米Ce_(1-x)Co_xO_(2-δ)固溶体的水热合成及表征

Hydrothermal Synthesis and Characterization of Nanometer Ce_(1-x)Co_xO_(2-δ) Solid Solutions

采用水热方法,在络合剂及氧化剂的辅助下合成出传统方法难以合成的Ce1-xCoxO2-δ固溶体.XRD结果表明,Ce1-xCoxO2-δ固溶体具有立方萤石结构;产物的平均粒度约为4nm.小半径、低价态Co离子的掺杂导致晶格收缩.结合XRD和Raman表征结果确定固溶体的固溶限约为x=0.06.紫外光谱分析结果表明,Co离子以混合价态(+2,+3)存在于CeO2晶格中,随着钴掺杂量的增大,带隙逐渐蓝移.低于固溶限样品的室温体相电导率随着钴含量增大而提高.

Using （NH4）2S208 and NH4OH as the oxidizer and chelating agent, respectively, Ce1-xCoxO2-δ solid solutions were synthesized under hydrothermal conditions and the optimum preparation parameters were explored. The obtained solid solutions had a cubic fluorite structure, and the average particle size was about 4 nm. The lattice parameter monotonously decreased with increasing the cobalt content. The solubility of x = 0.06 was determined by combining XRD and Raman techniques. Cobalt ions are found to be in a mixed valence state of Co^2＋ / Co^3＋ in CeO2 lattice. Increasing the cobalt content resulted in a clear blue shift of the absorption threshold edge and an increase of bulk conductivity.