Photoelectrochemical studies of oxide film of PbOn+SnOn obtained by potentiodynamic anodisation of Pb+Sn alloy electrode in alkaline medium

Thin film semiconducting oxides are synthesised by potentiodynamic anodisation of Pb + Sn alloy electrodes of various Sn content in hot alkaline sodium sulfate solution. The effect of Sn on the photoelectrochemical behaviour in Fe(CN)(6)(4-/3-) (pH 9.2, buffer) of lead oxide thin film prepared by this method is investigated. It has been concluded that the incorporation of tin into Pb + Sn alloy and its subsequent anodisation decreases the growth of photoactive alpha-PbO (tetragonal) phase and introduces a relatively very low photoactive SnO phase. The oxide layer formed after 20 min of anodisation of Pb-0.1wt.%Sn electrode shows the best photoresponse (conversion efficiency 0.23%), but it is lower than that obtained with undoped lead oxide (0.86%). The reasons for obtaining a low efficiency are discussed. The oxide layer is characterised by various physical and photoelectrochemical techniques. The growth of oxide film is found to be maximal in the potential range -1.25 to +2.35 V(vs. SCE).