Zhang J, Wu Z, Liu T, Hu L T, Wu Z, Ju X
Institute of High Energy Physics, Chinese Academy of Sciences, Beijing.
J Synchrotron Radiat. 2001 Mar 1;8(Pt 2):531-2. doi: 10.1107/s0909049500016022.
The aim of this work is the determination of Ce environment and valence state in Cerium oxide nanoparticles prepared by the microemulsion method. X-ray absorption near-edge structure measurements at Ce L3 edge were performed on the nanoparticles as a function of annealing temperature, ranging from 298K to 873K under air condition. The experimental results support the conclusion that Ce ion, in the investigated systems, is in trivalence state when the annealing temperature is below 473K. As the temperature increases up to 623K, the XANES spectrum shows the coexistence of Ce3+ and Ce4+ states. When the temperature is higher than 623K, the spectra become identical to that of CeO2 with a distinct double-peak structure, corresponding to the Ce4+ state.
本工作的目的是确定通过微乳液法制备的氧化铈纳米颗粒中铈的环境和价态。在空气条件下，对纳米颗粒进行了铈L3边缘的X射线吸收近边结构测量，测量结果作为退火温度的函数，退火温度范围为298K至873K。实验结果支持以下结论：在研究的体系中，当退火温度低于473K时，铈离子处于三价态。当温度升至623K时，X射线吸收近边结构光谱显示Ce3+和Ce4+态共存。当温度高于623K时，光谱变得与具有明显双峰结构的CeO2光谱相同，对应于Ce4+态。
