The Electrochemical Oxidation of Hydroquinone and Catechol through a Novel Poly-geminal Dicationic Ionic Liquid (PGDIL)–TiO2 Composite Film Electrode

Abstract

A novel poly-geminal dicationic ionic liquid (PGDIL)-TiO2/Au composite film electrode was successfully prepared by electrochemical polymerization of 1,4-bis(3-(m-aminobenzyl)imidazol-1-yl)butane bis(hexafluorinephosphate) containing polymerizable anilino groups in the electrolyte containing nano-TiO2. The basic properties of PGDIL–TiO2/Au composite films were studied by SEM, cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry. The SEM results revealed that the PGDIL–TiO2 powder has a more uniform and smaller particle size than the PGDIL. The cyclic voltammetry results showed that the catalytic effect on electrochemical oxidation of hydroquinone and catechol of the PGDIL–TiO2 electrode is the best, yet the Rct of PGDIL–TiO2 electrode is higher than that of PGDIL and TiO2 electrode, which is caused by the synergistic effect between TiO2 and PGDIL. The PGDIL–TiO2/Au composite electrode presents a good enhancement effect on the reversible electrochemical oxidation of hydroquinone and catechol, and differential pulse voltammetry tests of the hydroquinone and catechol in a certain concentration range revealed that the PGDIL–TiO2/Au electrode enables a high sensitivity to the differentiation and detection of hydroquinone and catechol. Furthermore, the electrochemical catalytic mechanism of the PGDIL–TiO2/Au electrode was studied. It was found that the recombination of TiO2 improved the reversibility and activity of the PGDIL–TiO2/Au electrode for the electrocatalytic reaction of HQ and CC. The PGDIL–TiO2/Au electrode is also expected to be used for catalytic oxidation and detection of other organic pollutants containing –OH groups.