The electrochemical characteristics of the mixture of 1-ethyl-3-methylimidazolium tetrafluoroborate and 1-ethyl-3-methylimidazolium iodide

The electrochemical behavior and characteristics of the interface between Bi(1 1 1) and 1-ethyl-3-methylimidazolium iodide solution in 1-ethyl-3-methylimidazolium tetrafluoroborate with variable concentrations were investigated by using cyclic voltammetry and electrochemical impedance spectroscopy. The shape of the complex impedance plane plots, the values of the phase angle and capacitance depend strongly on the concentration of EMImI in the mixture of ionic liquids, on ac frequency and on the electrode potential applied. The capacitance values increase considerably at potentials higher than −0.6 V vs. Ag|AgCl| mixture of RTIL, were the specific adsorption of iodide ions takes place. Comparison of the data for the Bi(1 1 1) electrode and the highly oriented pyrolytic graphite C(0 0 0 1) shows that the chemical nature and the crystallographic structure of an electrode significantly influence the specific adsorption of the halide ions. The non-linear least squares fitting method has been applied for calculation of equivalent circuit parameters for Bi(1 1 1)|mixture of RTIL interface.