Reversibility of photoelectrochromism at the TiO{sub 2}/methylene blue interface
- Univ. of Texas, Arlington, TX (United States). Dept. of Chemistry and Biochemistry
This paper describes the photoelectrochromic bleaching and recoloration of methylene blue in aqueous or methanolic slurry suspensions of TiO{sub 2}. Using simple modification of a UV-visible diode-array spectrometer setup, the spectral changes undergone by the dye in these solutions were monitored in situ during irradiation of the TiO{sub 2} particles and in the dark. A particular focus of this study was a systematic investigation of factors underpinning the chemical and electrochemical (kinetic) reversibility of the dye bleaching-recoloration sequence. Thus, choice of solution pH and hole capture agents is shown to be critical to the suppression of parasitic chemical and photochemical reactions involving the dye. On the other hand, dye adsorption on the TiO{sub 2} surface, the solvent medium itself, and its O{sub 2} content are all important factors in dictating the kinetic reversibility of the photoelectrochromic process. Finally, the practical implications of the findings are presented.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 533122
- Journal Information:
- Journal of the Electrochemical Society, Vol. 144, Issue 7; Other Information: PBD: Jul 1997
- Country of Publication:
- United States
- Language:
- English
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