Abstract
Nanofilm deposits of TiO2 nanoparticle phytates are formed on gold electrode surfaces by 'directed assembly' methods. Alternate exposure of a 3-mercapto-propionic acid modified gold surface to (i) a TiO2 sol and (ii) an aqueous phytic acid solution (pH 3) results in layer-by-layer formation of a mesoporous film. Ru(NH33+6 is shown to strongly adsorb/accumulate into the mesoporous structure whilst remaining electrochemically active. Scanning the electrode potential into a sufficiently negative potential range allows the Ru(NH3)3+6 complex to be reduced to Ru(NH3)2+6 which undergoes immediate desorption. When applied to a gold coated quartz crystal microbalance (QCM) sensor, electrochemically driven adsorption and desorption processes in the mesoporous structure become directly detectable as a frequency response, which corresponds directly to a mass or density change in the membrane. The frequency response (at least for thin films) is proportional to the thickness of the mass-responsive film, which suggests good mechanical coupling between electrode and film. Based on this observation, a method for the amplified QCM detection of small mass/density changes is proposed by conducting measurements in rigid mesoporous structures.
Original language | English |
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Pages (from-to) | 286-291 |
Number of pages | 6 |
Journal | Electrochemistry Communications |
Volume | 5 |
Issue number | 4 |
DOIs | |
Publication status | Published - 1 Apr 2003 |
Keywords
- Adsorption
- Bioinorganic composite materials
- Density response
- Directed assembly
- Nanoparticles
- Phytic acid
- Quartz crystal microbalance
- TiO
- Voltammetry
ASJC Scopus subject areas
- Electrochemistry