X-ray absorption fine structure study on residue bromine in carbons with different degrees of graphitization

✍ Scribed by Hidetaka Yoshikawa; Katsuya Fukuyama; Yoichiro Nakahara; Takehisa Konishi; Nobuyuki Ichikuni; Yasuko Yoshikawa; Noboru Akuzawa; Yoichi Takahashi; Keiko Nishikawa

• Book ID: 104106750
• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 271 KB
• Volume: 41
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/s0008-6223(03)00400-7

✦ Synopsis

The structure of bromine residue compounds was investigated by X-ray absorption fine structure (XAFS) in order to interpret where and how bromine is present in carbons with different degrees of graphitization. The residue compounds can be classified into three groups, as obtained from X-ray absorption near edge structure (XANES) spectra and the values of the intramolecular distance r determined by extended X-ray absorption fine structure (EXAFS). In Group I, prepared from Br -Br the host carbons heat treated at temperatures higher than 1900 8C, bromine exists in the interlayer space of graphite in the form of Br molecules with interaction of the p electrons of graphite. In Group III, from carbon heat treated at 1000 8C, most 2 of the bromine probably reacts with carbon atoms having a dangling bond or functional groups. For Group II, where the host carbons are heat treated at intermediate temperatures, it is likely that bromine exists in undeveloped defects with a unique electronic state.