The electrochemical oxidation of tetrabutylammonium carboxylates on carbon surfaces is typically performed following a global non-Kolbe mechanism [1], whose reactive intermediates allow the grafting of carbon surface with organic moieties [2]. Several characterisation strategies have been used to obtain information about the properties of the grafted film, among them is the use of reversible redox probes [3]. In this case, it has been observed that that the behaviour of the redox probe on the grafted surface is not stable and varies during cycling procedures in cyclic voltammetry [4]. Therefore, in this work, grafted carbon surfaces bearing alkyl-ester, alkyl-ketone, alkynyl and saturated chains were prepared to demonstrate that the variability in the behaviour of 1,4-benzoquinone as redox probe is due to a reversible reorganization effect of the grafted film [5]. The voltammograms of the first reduction wave of the redox probe on the different modified electrodes change during cycling procedures. However, the stand time of these modified electrodes in the electrolyte solution allows the recovery of the initial voltammograms. The changes observed between cycling and stand time are cyclical and can be understood through a reversible reorganization effect of the grafted film, which is attributed to hydrogen bonding interactions between the functional groups present in the structure film and the water present in solvent.

References

[1] H.J. Schaeffer, Topics in Current Chemistry, 1990, 152, 90

[2] C.P. Andrieux, F. González, J.M. Savéant, J. Am. Chem. Soc., 1997, 119 4292

[3] A.C. Cruickshank, E.S.Q. Tan, P.A. Brooksby, A.J. Downard, Electrochem. Commun., 2007, 9 1456-1462.

[4] A.O. Solak, L.R. Eichorst, W.J. Clark, R.L. McCreery, Anal. Chem., 2003, 75, 296

[5] D. Morales-Martínez, F.J. González, Electrochem. Commun., 2016, 62, 21