Electrochemical behavior of tetrafluoro-p-benzoquinone at the presence of carbon dioxide: Experimental and theoretical studies

The electrochemical behavior of p-benzoquinone, BQ, and tetrafluoro-p-benzoquinone, TFBQ, in the DMF solvent in the absence and the presence of carbon dioxide, CO2, were studied by means of cyclic voltammetry. An EE mechanism is proposed for reduction of both species of BQ and TFBQ in the absence of CO2. Voltammogram of BQ at the presence of CO2 showed a new redox couple with characteristics that are different from those observed for electrochemical reaction of BQ in the absence of CO2. The mechanism ECiE was proposed for electrochemical reduction of BQ in the presence of CO2. The results indicate that the lifetime of the BQ reduction product, anion radical of BQ, in the presence of CO2 is much shorter than the time window of the used voltammetric method. The electrochemical behavior of TFBQ in the presence of CO2 is fully different from that observed for BQ reduction in the presence of CO2. The second redox couple potentials of TFBQ are significantly shifted when CO2 is presented in the solution and the shift values are dependent on the CO2 concentration. Finally, an EECr mechanism was proposed for electrochemical reaction of TFBQ in the presence of CO2 in the DMF solvent. (C) 2016 Elsevier Ltd. All rights reserved.