Surface characterisation of anodic films of Pb-Sn alloy electrodes: the effect of Sn on the photoelectrochemical properties

Oxide thin films of Pb-Sn alloy electrodes were synthesised by potentiodynamic anodisation in hot alkaline solution of sodium sulfate. Films were characterised by various analytical techniques: XRD, SEM, Raman spectroscopy and XPS. The XRD and Raman investigations reveal that the increase in concentration of Sn in the alloy suppresses the formation of the photoactive phase alpha-PbO but it increases the formation of the conducting phase, alpha-PbO2. XPS results indicate the presence of both divalent and tetravalent Pb as well as tetravalent Sn on these films. It also gives evidence for the decrease in alpha-PbO content upon anodisation of the alloy Pb-Sn electrodes.