Effect of Sb on the properties of anodic Pb(II) oxide film formed in alkaline solution

Abstract

A b s t r a c t The composition and properties of the anodic films formed on P b and Pb-3at.xSb alloy at -0.10 V (vs. Hg/HgO) for 2.5 h in 0.1 mol.dmT3 NaOH solution (25OC) were investigated by cyclic voltammetry, linear sweep voltammetry, open circuit decay curve, photocurrent technique, X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the anodic film iormed on P b mainly consists of t-PbO, while that on Pb-3at.%Sb consists of o-PbO, t-PbO and a small amount of orthorhombic SbzO3. The dominant component of the film anodically grown on Pb-3at.%Sb for less than 5 min is o-PbO, however, t-PbO is the major component of the anodic film formed for 1 h or longer. It is estabbhed that Sb suppresses the growth of t-PbO. The anodic film formed on Pb-3at.%Sb is less porous than that on Pb. The bandgap energies of t-PbO and o-PbO in the films were determined by photocurrent measurements to be 1.83-1.84 eV and 2.60 eV, respectively. Keywords Anodic Pb(I1) oxide film, lead, Pb-Sb alloy E x p e r i m e n t a l Cyclic voltammetry (CV), linear sweep voltammetry (LSV) and open-circuit decay curve (OCD) methods were carried out using a PAR Model 273 potentiostat/galvanostat