ELECTROCHEMICAL CHARACTERIZATION OF GLASSY CARBON ELECTRODES MODIFIED WITH SWCNT FUNCTIONALIZED WITH DIAZONIUM SALT

Abstract

Although carbon nanotubes have unique properties, one of the biggest drawbacks in practice is the difficulty in forming dispersions of individual nanotubes in a given solvent. Covalent functionalization of carbon nanotubes allows the incorporation of chemical groups at the nanotube surface that, according to its polarity, facilitates the dispersibility in different solvents. In this work, singled-wall carbon nanotubes were functionalized by spontaneous grafting with a diazonium salt obtained from the 4-aminobenzoic acid to obtain SWCNT-pB. The nanomaterial obtained was characterized by several methodologies that the covalent incorporation of the functional groups. SWCNT-pB were dispersed in ethanol/water 50% V/V under ultrasonic treatment, and the exfoliation degree was evaluated by UV-Vis spectrophotometry. under optimal conditions, SWCNT-pB dispersion was stable for more than 45 days. Glassy carbon electrodes (GCE) modified with the nanomaterial show significant increases in their capacitive current and a faradaic process due to redox species confined on the surface of SWCNT-pB whose anodic peak currents depend linearly with the scan rate. The modified electrodes also show a catalytic response towards ascorbic acid (AA) and notorious increments in the oxidation and reduction currents of H2O2. The stability of the dispersions and the excellent electrochemical responses obtained make this nanomaterial very interesting for its application in electrochemical detection.