Structure, morphology and photoelectrochemical responses of anodic PbO films formed on Pb electrodes in various concentrations of alkaline solution

Abstract

The anodic behavior of the Pb electrode in various NaOH concentrations maintained at 80 °C has been investigated with the use of cyclic voltammetry. The influence of NaOH concentration on the composition, surface morphology, and semiconducting properties of the potentiostatically (at 0.1 V vs. SCE) prepared anodic PbO films was analyzed with the help of X-ray diffractometry, scanning electron microscopy and photoelectrochemical methods. The XRD data of the anodic oxide films indicate the presence of the α-PbO phase, and such films exhibit strong 110 orientation when prepared in 0.05 to 0.5 M NaOH solutions. Thickness values of the anodic films were estimated by a cathodic reduction technique. Nearly 25μm thick PbO film can be obtained as a maximum limit of thickness when anodization is performed in 0.4M NaOH solutions for about 90 min. The anodic films prepared in NaOH concentrations between 0.05 and 0.1 M exhibit the highest quantum yield for anodic photocurrent generation to visible monochromatic irradiation in 0.1 M Fe(CN) 6 3−/4− electrolyte. Factors affecting the extent of photoactivity and the nature of the spectral response curves are discussed.