Voltammetry of Undiluted Red‐Ox Systems. Electrochemical ESR‐ and Electrochemical Impedance Spectroscopy Evidence for Formation of Ionic Liquid at Microelectrode Surface

It is believed that voltammetry of undiluted red‐ox liquids can lead to the formation of stable thin layers of ionic liquids at the microelectrode surface. Such situation was postulated for several liquids (solvents), however, so far no hard evidence supporting this expectation was obtained. By using electron spin resonance in combination with voltammetric experiments and electrochemical impedance spectroscopy we have shown that the concentration of the cation radicals at the microelectrode surface may be high (nitrobenzene) and the overall resistance of the solution abruptly drops (methanol) when the potential at the microelectrode corresponds to the wave plateau of the undiluted organic liquid. Both facts constitute a good evidence for the formation of microlayers of ionic liquids at the microelectrode surface during electrolysis of undiluted red‐ox systems.