Bi掺杂改性MnO<sub>2</sub>的EXAFS研究

Bi掺杂改性MnO₂的EXAFS研究

基金项目:

北京市教委科技发展及BSRF共同资助资助项目(97050501)

详细信息

1. College of Environment and Energy Engineering, Beijing Polytechnic University, Beijing, 100022;
2. Institute of Chemistry and Chemical industry, Xiang Tan University, Xiang Tan, 411105;
3. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100039

摘要: 应用扩展X射线精细结构研究(EXAFS)技术研究了改性MnO₂结构变化.结果表明;改性后MnO₂中第1配位壳层Mn-O配位数降低,第2壳层没有变化,第3壳层的Mn-Mn配位消失.说明掺杂原子进入了MnO₂晶格中,并且增大MnO₂的不同壳层配位无定形.在线EXAFS吸收谱分析表明;在MnO₂放电还原过程中,与未改性相比,随着还原深度加大,掺杂改性后的MnO₂中Mn的第1、第2壳层配位向无定形转变减慢,配位数变化不明显,而且在一电子放电深度,没有发生结构重排.
- EXAFS /
- MnO₂ /
- 无定形
Abstract: A short range structure investigation of modified MnO₂ was made using the extend X-ray absorption fine structure method (EXAFS). As it turned out that the coordination mumber of the first shell of the Mn atom decreases upon modification,while no change happens to the second sell, and the Mn-Mn coordination to the thirdshell disappeares. The dopant bismuth exists in the lattice of modified MnO₂. The abeorption spectra of Mn K-edge on line shows that with the electro-discharge reduction,the deeper of the reduction the slower of the process in which the local structure around the Mn atom is transferred into the disorder and the vaguer the change of the coordination number, compared with one of non-modified MnO₂. Furthermore there is no structural rearrangement of Mn atoms during the l-e discharge.
- EXAFS /
- MnO₂ /
- disorder