Study of the underpotential deposition of copper onto polycrystalline palladium surfaces

The underpotential deposition of copper onto a palladized Pt electrode has been studied. It has been shown that Cl− ion traces and adsorbed Cu atoms form a catalyst on the Pd surface which accelerates Pd corrosion during the desorption of adsorbed Cu. The Pd2+ ions formed in this corrosion process may bring about Cu/Pd alloy deposition, suggesting alloy formation owing to copper absorption. The quantities of copper and oxygen adsorbed on the same palladium surface are roughly equal. A mechanism of copper deposition via ionization of presorbed hydrogen is proposed.