An insight into the thin-layer diffusion phenomena within a porous electrode: Gallic acid at a single-walled carbon nanotubes-modified electrode

The electrochemical behavior of gallic acid at a single-walled carbon nanotubes-modified glassy carbon electrode, in an acetate buffer, a model wine buffer and the Britton-Robinson buffer was studied. The elucidation of phenomena, related to the electrochemical behaviour, was performed using cyclic voltammetry and chronoamperometry. Analysis of chronoamperometric results revealed that overall processes, responsible for current signal are mostly related to diffusion phenomena. These phenomena can be divided into four processes that take place either in a thin-layer or/and in a solution depending on the buffer used. By comparative analysis of chronoamperometric and voltammetric results in real time, the effects of scan rate, concentrations of gallic acid and layer thickness have on voltammetric signal are discussed in the light of diffusion processes that take place in thin-layer. Finally, comparative analyses of cyclic voltammograms and chronoamperograms, recorded at different pH values, have revealed that low sensitivity at high pH values can be attributed to hampered diffusion. These findings can be useful in elucidating electrochemical behaviour of various species (not only of gallic acid) using an electrode containing carbon nanotubes.

Automated summary

The electrochemical behavior of gallic acid on a single-walled carbon nanotubes-modified electrode was investigated using cyclic voltammetry and chronoamperometry. Diffusion phenomena were found to be responsible for the overall current signal, and these phenomena were divided into four processes occurring in thin-layer or solution. The effects of scan rate, gallic acid concentration, and layer thickness on the voltammetric signal were discussed based on the diffusion processes in the thin-layer.