Diffusion of redox active molecules in deep eutectic solvents

Stéphanie Fryars (1) , Emmanuelle Limanton (1) , Fabienne Gauffre (1) , Ludovic Paquin (1) , Corinne Lagrost (1) , Philippe Hapiot (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

Classical electrochemical approaches were evaluated for investigating the basic properties of deep eutectic solvents (DES) with a special focus on the mass transport phenomena and diffusion of charged species in DES. Three classical DES were considered: Reline, Ethaline and choline chloride-lactic acid mixture. Cyclic voltammetries of the ferrocene oxidation and of the ferricyanide reduction, respectively with charge 0 and − 3, exhibit well-defined responses in these media. For all considered DES and redox molecules, diffusion processes govern the mass-transport of the redox molecules from the solution to the electrode. Derived diffusion coefficients were extracted and found to present some inconsistencies with the classical Stokes-Einstein law for homogeneous media. The diffusion coefficients were found to be almost unaffected by the charge present on the diffusing molecules contrarily to observations made for ionic liquids.

Keywords: Deep eutectic solvents; Redox probes; Cyclic voltammetry; Diffusion coefficients

Domains: Chemical Sciences; Other

Stéphanie Fryars, Emmanuelle Limanton, Fabienne Gauffre, Ludovic Paquin, Corinne Lagrost, et al.. Diffusion of redox active molecules in deep eutectic solvents. Journal of Electroanalytical Chemistry, 2018, 819, pp.214-219. ⟨10.1016/j.jelechem.2017.10.030⟩. ⟨hal-01812103⟩