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Effects of ethanol treatment on thin-layer phenomena in "apparently 2D and 3D carbon nanomaterials": Gallic acid at graphene and single-walled carbon nanotubes

A modification of a glassy carbon (GC) surface usually includes carbon nanomaterials (CNMs) in order to study the redox behaviour of molecules of interest. The most important benefit of CNMs is "promotion of electron transfer". This phenomenon is often related to “faster electron transfer kinetics” that is commonly interpreted in terms of “electrocatalysis". However, this often results in neglecting the influence of diffusion phenomena in CNMs. This could lead a naive electrochemist using the semi-infinite model to infer an enormously large charge-transfer rate constant. Indeed, our results suggest different influence of ethanol pretreatment of certain CNMs on their electrochemical properties, which cannot be explained by "electrocatalysis". Based on our previous research, the elegant approach to the elucidation of the mentioned phenomena in terms of "thin-layer" diffusion was presented. In addition, the differences between "apparently 1D and 2D" CNMs were explained. For this purpose, the voltammetric as well as chronoamperometric methods were employed and diffusion parameters were calculated. Additional insight into the complex mass transport regime was obtained by electrochemical impedance spectroscopy. Finally, the observed phenomena were confirmed by insight into the geometrical structure using scanning electron microscopy. These phenomena were investigated on gallic acid behavior on single-walled carbon nanotube and graphene modified GC.

Carbon nanomaterials ; Thin-layer diffusion ; Voltammetry ; Chronoamperometry ; Gallic acid.

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