Electroreduction of carbon monoxide on palladium electrodeposits in solutions containing copper ions

It is shown that the electroreduction of CO proceeds on electrolytic deposits of palladium (edPd) in 0.5 M H2SO4 + (1–5) mM CuSO4 + CO(sat) solutions at the potentials more positive than the Cu2+/Cu equilibrium potential. Among the CO reduction products, methanol and formaldehyde are identified. The current efficiency with respect to CH3OH exceeds 75% on edPd formed in 1% PdCl2+0.5 M H2SO4 solutions. In addition, Cu+ ions, which probably form complexes with CO, are detected in the solution and are assumed to play the role of intermediate species in the mediator catalysis along with copper adatoms.