Abrasively Immobilised Multiwalled Carbon Nanotube Agglomerates: A Novel Electrode Material Approach for the Analytical Sensing of pH

We demonstrate for the first time that agglomerates of multiwalled carbon nanotubes (MWCNTs) can be formed in which the binder in the agglomerate is itself a redox‐active molecular solid. Two separate agglomerates were formed by dissolving 9,10‐phenanthraquinone (PAQ) or 1,2‐napthaquinone (NQ) in ac...

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Bibliographic Details
Published in:Chemphyschem 2004-05, Vol.5 (5), p.669-677
Main Authors: Wildgoose, Gregory G., Leventis, Henry C., Streeter, Ian, Lawrence, Nathan S., Wilkins, Shelley J., Jiang, Li, Jones, Timothy G. J., Compton, Richard G.
Format: Article
Language:English
Subjects:
Analytical chemistry
Chemistry
Chemistry, Physical - methods
Electrochemistry
Electrons
Exact sciences and technology
General, instrumentation
Hydrogen-Ion Concentration
Microscopy, Electron, Scanning
Models, Molecular
modified carbon electrodes
multiwalled carbon nanotubes
nanostructures
Nanotubes, Carbon - chemistry
Nanotubes, Carbon - ultrastructure
Naphthoquinones - chemistry
Oxidation-Reduction
Phenanthrenes - chemistry
sensors
Temperature
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Summary:We demonstrate for the first time that agglomerates of multiwalled carbon nanotubes (MWCNTs) can be formed in which the binder in the agglomerate is itself a redox‐active molecular solid. Two separate agglomerates were formed by dissolving 9,10‐phenanthraquinone (PAQ) or 1,2‐napthaquinone (NQ) in acetone together with MWCNTs and adding an excess of aqueous solution to cause precipitation of agglomerates, approximately 10 µ;m in dimension, which consist of bundles of nanotubes running into and throughout the amorphous molecular solid that binds the agglomerate together. The nature of this structure, when immobilised on a substrate electrode and in contact with aqueous electrolyte solutions, gives rise to many three‐phase boundaries, electrolyte|agglomerate|conductor, which is advantageous to the solid‐state analytical electrochemistry of such a material as it imparts a larger electroactive surface area than other modified carbon electrodes. The two agglomerates each gave a voltammetrically measurable response to changes in pH; when abrasively immobilised on a basal plane pyrolitic graphite electrode a plot of peak potential against pH produced a linear response for both MWCNT–PAQ and MWCNT–NQ agglomerates over the pH range pH 1–12 and over the temperature range 20–70 °C. Many three‐phase boundaries: The authors demonstrate for the first time that agglomerates of multiwalled carbon nanotubes can be formed in which the binder in the agglomerate is itself a redox‐active molecular solid (see picture). The nature of this structure, when immobilised on a substrate electrode and in contact with aqueous electrolyte solutions, gives rise to many three‐phase boundaries, which imparts a larger electroactive surface area than other modified carbon electrodes.
ISSN:1439-4235
1439-7641
DOI:10.1002/cphc.200400030