Stabilization of free radical intermediates on metal oxide semiconductors surfaces
- Creators
- Bahnemann, Detlef W.
-
Hoffmann, Michael R.
- Other:
- Ginley, D. S.
Abstract
Free radicals intermediates are formed on the surface of metal oxide semiconductors, namely TiO_2 and Fe_2O_3, following the light-induced charge separation upon band-gap illumination. These radicals appear to adhere strongly to the surfaces of the small colloidal particles (diameters between 5 and 20 nm) employed in this study. A second electron-transfer step yielding the observed end-products therefore preceeds desorption of the reactive intermediates. Oxidation of methylviologen (1,1'-dimethyl-4,4'-bipyridylium chloride) and reduction of halothane (2-bromo-2-chloro-1,1,1- trifluoroethane) is thus found to proceed with high quantum yields and very specific mechanisms on colloidal TiO_2. The oxidation of sulfite on α-Fe_2O_3 particles yields the sulfite radical anion, SO_3^- , as initial intermediate. A subsequent electron transfer leading to the formation of sulfate occurs on the surface of the same catalyst particle.
Additional Information
© 1988 Electrochemical Society. The scientific collaboration with Ors. Ch.-H. Fischer and J. Mönig and Ms. J. Kern in different parts of this project has been stimulating and successful. DWB thanks the Hahn-Meitner-Institut for granting him a leave of absence.Attached Files
Published - 398475.pdf
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Additional details
- Eprint ID
- 59906
- Resolver ID
- CaltechAUTHORS:20150826-103411675
- Created
-
2015-09-11Created from EPrint's datestamp field
- Updated
-
2022-10-24Created from EPrint's last_modified field
- Series Name
- Electrochemical Society Proceedings
- Series Volume or Issue Number
- 88-14