Copper Ion Catalyzed Electroreduction of Carbon Monoxide on Iridium Electrode

Substantial cathodic currents are observed on iridium electroplates in 0.5 M H 2 SO 4 + (0.001–0.005 M) CuSO 4 + CO (sat) at potentials positive with respect to the Cu/Cu 2+ equilibrium potential. These currents are shown to correspond to electroreduction of both CO and Cu 2+ ions to Cu + , where the latter ions are formed in amounts indicating the formation of complexes. Among the products of CO reduction, methanol and formaldehyde are identified. A possible mechanism of CO reduction is discussed. It is assumed that both copper adatoms and Cu + ions can play the role of intermediates in the mediator catalysis.