Electroreduction of carbon dioxide at a lead electrode in propylene carbonate: A spectroscopic study

The electrochemical reduction of carbon dioxide at a lead electrode was studied in propylene carbonate (PrC) containing tetraethylammonium perchlorate (TEAP) as electrolyte. Different electrochemical techniques such as cyclic voltammetry and chronoamperometry were used to evaluate the catalytic activity of this material towards CO2 electrodimerization. The electroreduction process was also investigated by in situ infrared reflectance spectroscopy in order to determine adsorbed intermediates and reaction products. The peak of reduction observed in cyclic voltammetry starting at −2.05 V vs. Ag/AgCl has been clearly ascribed to the carbon dioxide reduction by SPAIRS technique. Infrared reflectance spectroscopy also confirmed the absence of CO at the lead cathode during chronoamperometric measurements and that oxalate has been formed concurrently to the CO2 consumption. Combining the analytic and spectroscopic results, a reaction mechanism was proposed for the reduction of carbon dioxide to oxalate ions on a lead cathode in a nonaqueous aprotic medium.