Synthesis And Studies On Modified Electrodes Of Polyaniline Film And Four α, α'-Dioxoketene Cyclic Dithioacetals

The main work of this paper consists of two parts. The first one is that, we studied the electrochemistry and the spectrum nature of four α, α'-Dioxoketene Cyclic Dithioacetals. The other is the electrochemical growth of Aniline on glassy carbon (GC) electrodes in several kinds of organic solvents and sulfuric acid solutions. It is investigated that these modified electrodes showed the electrocatalytic activity of ascorbic acid (AA).(1) The electrochemical and spectral properties of four α, α'-Dioxoketene Cyclic Dithioacetals have been studied by CV, UV-vis spectroscopy and FTIR spectroscopy in organic solvent DMF system. All these compounds have only one quasi-reversible peak around -1.4V-1.6V at platinum microelectrode. According to the CV data, we calculated some electrochemical constants of each of compounds in DMSO solution. The self-assembled monolayer of these compounds has been prepared on gold electrode, investigating by EIS and XPS. The ac impendence of all compounds appears semicircle in the high frequencies, and there is a typical peak in XPS spectrum. The Cyclic voltammogram peak potential, some bands of UV and semicircle diameter is influenced by the number of methylenes and the substituting groups at one point of a ketone.(2) The modified electrodes were prepared in the mixed solution containing sulfuric acid and three kinds of organic solvents (DMF, CH3CN and CH3OH) separately using cyclic voltammetry (CV). The PANI/ITO film was measured using UV-vis and FTIR spectroscopy to show the influence of different organic solvents. Then the electrocatalytic oxidation process of AA was studied with all kinds of modified electrodes by CV and LSV at lower scan rate. There were two oxidation peaks in LSV curve. One is corresponded to the oxidation of AA, and the other appearing at 0.2V is corresponded to the oxidation of PANI from leucoemeraldine to emeraldine state. Compared with the electrochemical behavior of modified electrode synthesis in sulfuric acid, the potential separation between the two peaks and the current increased when the modified electrode synthesis in mixture solution adding organic solvent was used. All kinds of modified electrodes show strong electrocatalytic activity to AA. However, organic solvent can influence the structure of PANI film.