X-Ray Photoelectron Spectra of Lead Oxides

ESCA spectra of seven different lead-oxygen species are examined including adsorbed oxygen on lead, two crystal forms of PbO, Pb₃O₄, PbO₂, and two forms of adsorbed water on PbO2. The spectrum of Pbs04 exhibits the behavior to two PbO molecules and one PbO₂ molecule although specific characterization of the crystal structure of PbO in Pb₃O₄ could not be made. The binding energies of the Pb 4f electrons in PbO₂ are found to be lower than those of the Pb 4f electrons in PbO. The apparent revesal is rationalized in terms of a relaxation effect. Two kinds of adsorbed water are also found on PbO₂- These are explained in terms of a surface adsorbed water species and a water or hydroxyl species which occupies lattice vacancies near the surface. These spectra were then used to characterize electrochemically generated Pb02. It is proposed that this technique may prove valuable in characterizing these electrochemically produced materials.