Abstract: The electrochemical reduction of CO₂ on copper electrode was investigated in acetonitrile(MeCN), dimethyl formamide(DMF) and dimethyl sulfoxide(DMSO) containing 0.1 mol/L tetraethylammonium bromioe(TEABr) by cyclic voltammetry and chronocoulometry at 298 K and under atmospheric pressure. There were obviously irreversible one-electron reduction peaks after saturated with CO₂ on copper electrode in three solvents, which generated anion radical of CO₂. The influence of scan rate was also studied by cyclic voltammetry. The diffusion coefficients of CO₂ in MeCN, DMF and DMSO were 8.981×10^-6, 1.019×10^-6 and 1.032×10^-6 cm²/s and the transfer coefficients were 0.064, 0.042 and 0.059, respectively. These results show that the electroreduction of CO₂ was an irreversible diffusion controlled process.

Key words: Carbon dioxide, Copper electrode, Cyclic voltammetry, Chronocoulometry