Quantum-Chemical Investigation of Pb 2+ Ion Adsorption at Au(111) from Alkaline Medium

The interaction of lead hydroxides with gold surface in alkaline medium is studied by the density functional theory using the cluster model of the metal surface. For this interaction, its geometrics and energetics were estimated. The electron structure of the system has been analyzed. The d-orbital of gold and p‑orbital of oxygen are shown to mainly contribute to the formation of the system’s molecular orbitals. Because the contributions of s- and p-orbitals being comparable, the role of lead in less significant. Under alkaline conditions, the lead hydroxides’ adsorption is based on their interaction with OH– ions adsorbed at gold. The $${\text{Pb}}({\text{OH}})_{{\text{3}}}^{ - }$$ hydroxo-complex is shown to be the most probable form of lead hydroxides existing at the gold surface.