Reduction of carbon dioxide on modified glassy carbon electrodes

Electrochemical reduction of carbon dioxide on glassy carbon (GC) was studi ed by applying different potential regimes and monitoring the effect of the electrode surface conditioning, as well as the nature of supporting-electr olyte, upon the nature of the reaction. In the case of constant potential e lectrolyses, a rapid decay of the cathodic current was observed, while appl ication of a suitable pulse program to the working electrode, in addition t o the ultrasonic cleaning of the surface, allowed completion of the reactio n without premature current downfall. Modification of the electrode surface , by applying potential pulses, caused a decrease of the reduction potentia l of CO2 on glassy carbon. High yields in carbon monoxide and methanol were obtained in these media, with the highest value obtained for methanol in s odium chloride and carbon monoxide in ammonium oxalate. (C) 1999 The Electr ochemical Society. S0013-4651(97)10-103-3. All right reserved.