The electrochemical behavior of titanium dioxide film in Lewis basic AlCl3-1-butyl-3-methylimidizolium ionic liquid

The electrochemical behavior of titanium dioxide film in Lewis basic AlCl3-1-butyl-3-methylimidizolium ionic liquid (AlCl3-BMIC) at room temperature was investigated by means of potentiodynamic polarization; cyclic voltammetry; sampled current voltammetry and electrochemical impedance spectroscopy (EIS). It was found that as the TiO2 film thickness increased, a cathode inhibition effect of the oxide film on the reduction process was strengthened, which means that a greater overpotential was required to initiate the reduction process. In the EIS test, the preferable equivalent circuit was made to fit the experimental data and fitted parameters were obtained. Additionally, increasing reaction temperature can make the cathode depolarization. In the end, the model for this reduction process has been given on the basis of the pictures of reduced TiO2 film and the electronic energy band structure models.

► A cathode inhibition effect of the TiO2 film was strengthened by the increased film thickness. ► The preferable equivalent circuit has been made. ► Increasing reaction temperature can weaken the cathode polarization. ► The model for this reduction process has been given.