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

Electrochemical adsorption-desorption of lead atoms (Pb-ad) on a gold elect rode 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 adato ms depend on the presence of submonolayer or supermonolayer amounts of a ch alcogen. The underpotential deposition of lead adatoms on Au/Se-ad and Au/T e-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 stru ctures have rather long storage times (dozens of minutes) in aqueous acid s olutions of HNO3 saturated with argon.