Carbon Dioxide Reduction at a Metal Phthalocyanine Catalyzed Carbon Electrode

Metal phthalocyanines deposited on carbon electrodes have been found to catalyze the electroreduction of carbon dioxide to formic acid in acid solutions . The overpotential for reduction on cobalt phthalocyanine is approximately 200 mV lower than on the best metal cathodes at currents up to 10 mA/cm2. The main reaction product in long‐term electrolysis is the formate ion at . Methanol is also produced at lower pH values. The phthalocyanine becomes inactive in the less acid solutions once a fairly negative potential is imposed, probably due to an irreversible reduction of the catalyst.