In-situ spectroelectrochemistry of adsorbed methylene blue on a sulphur-modified gold electrode
The properties of a methylene blue layer adsorbed onto a sulphur-modified gold electrode have been studied by electrochemical and in-situ reflectance spectroscopy in the visible region. At saturation coverage, methylene blue monomer and dimer bands were observed in the double-layer region through th...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 1991 |
| País: | Argentina |
| Institución: | Universidad Nacional de La Plata |
| Repositorio: | SEDICI (UNLP) |
| Idioma: | inglés |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/121358 |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/121358 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Exactas Química Spectroelectrochemistry Methylene Sulphur-modified gold electrode |
| Sumario: | The properties of a methylene blue layer adsorbed onto a sulphur-modified gold electrode have been studied by electrochemical and in-situ reflectance spectroscopy in the visible region. At saturation coverage, methylene blue monomer and dimer bands were observed in the double-layer region through the electrochromism of the adsorbed film arising from the effect of the double-layer field on the molecule transition moment. Possible dye orientations in the adsorbed state are discussed with the aid of the optical measurements. At low surface concentrations, the optical signal stems from modulation of the monomer/dimer interconversion. Repeated electrochemical reduction and oxidation of adsorbed methylene blue result in gradual desorption of the dimer species, probably due to a change in the molecular geometry upon reduction which may evolve from a planar configuration to a folded structure. |
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