SURFACE DISTRIBUTION AND ELECTRON-TRANSFER REACTION OF OSMIUM COMPLEXMEDIATOR ENTRAPPED ON POROUS CARBON ELECTRODE

Citation
K. Miyata et al., SURFACE DISTRIBUTION AND ELECTRON-TRANSFER REACTION OF OSMIUM COMPLEXMEDIATOR ENTRAPPED ON POROUS CARBON ELECTRODE, Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 66(2), 1998, pp. 186-193
Citations number
12
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Electrochemistry
ISSN journal
0366-9297
Volume
66
Issue
2
Year of publication
1998
Pages
186 - 193
Database
ISI
SICI code
0366-9297(1998)66:2<186:SDAERO>2.0.ZU;2-3
Abstract
Enzyme-sensors using a porous carbon electrode with an Os complex as a redox mediator have been described in previous studies. In this paper , the distribution of the Os complex adsorbed on the porous carbon, co mpared with plastic formed carbon (PFC), and the electron transport me chanism were examined by XPS, CV and PSCC methods, respectively. XPS r esults showed that the outermost surface of the porous carbon was main ly covered with a Nafion layer, and the Os complex was present in the inner pores of the porous carbon, indicating it has passed through the Nafion layer. In contrast, the Os complex existed mainly in the Nafio n layer on PFC electrode, on the basis of the XPS spectra. These resul ts were confirmed by electrochemical analyses. The diffusion coefficie nt for the Os complex on the porous carbon was found to be 8.92 x 10(- 12) cm(2)/sec, based on PSCC analysis. This value is about 20 times hi gher than that of the Os complex passing through the Nafion layer, and increased with an increase in its concentration, These results sugges ted that the charge on the Os complex, produced by the redox reaction, was transported into the electrode via electron self-exchange.