Anodic oxidation of Pb-In alloys in alkaline solution: Effect of In on electrochemical and photoelectrochemical behaviour of lead oxide

The electrochemical behaviour of Pb-In alloy (containing different concentrations of In) is studied in the potential range -0.75 to +1.25 V with a sweep rate 200 mV s(-1) at 80 degrees C in 0.1 M NaOH, 0.1 M Na2SO4 solution. It is observed that incorporation of In in Pb helps to passivate lead from oxidation and subsequently reduces the photoactivity of the oxide film grown over Pb-In alloy. XRD, XPS and Raman studies of the oxide films indicate that alpha-PbO is the major phase of the film, with PbO2 and In2O3 as minor phases. Among the various concentrations of Pb-In alloys, lead oxide obtained over the Pb-0.3 wt% In alloy gave the best photoactivity. The open-circuit voltage (V-oc) and short-circuit current (I-sc) of a photoelectrochemical cell (PEC) of configuration: In-doped PbO (1 cm(2)) thin film (obtained from Pb-0.3 wt% In alloy electrode)/0.1 M K4Fe(CN)(6), K3Fe(CN)(6) (pH = 9.2, buffer)/Pt (2 cm(2)) is 860 mV and 3.2 mA cm(-2), respectively. (C) 1998