Lead adatoms on submonolayers of selenium and tellurium deposited on a gold electrode

Electrochemical adsorption-desorption of lead atoms (Pb-ad) on a gold electrode covered by submonolayers of selenium and tellurium (Au/Se-ad, Au/Te-ad) is studied at potentials exceeding the equilibrium potential of the Pb(II)-Pb(0) system. Cyclic voltammetry reveals that energy states of lead adatoms depend on the presence of submonolayer or supermonolayer amounts of a chalcogen. The underpotential deposition of lead adatoms on Au/Se-ad and Au/Te-ad is irreversible, which is due to the formation of chemical bonds Pb-Se and Pb-Te. Electrochemical adsorption of lead atoms on Au/Se-ad and Au/Te-ad leads to the formation of submonolayers of lead chalcogenides Au/PbSead and Au/PbTead. Stability of submonolayer structures of Au/Se-ad, Au/Te-ad, Au/PbSead, and Au/PbTead is studied under open-circuit conditions. The structures have rather long storage times (dozens of minutes) in aqueous acid solutions of HNO3 saturated with argon.