Electrochemical deposition of lead dioxide in the presence of polyvinylpyrrolidone - A morphological study

In this work, we investigate the effect of polyvinylpyrrolidone (PVP) on the morphology and the interfacial properties of lead dioxide (PbO2). The electrodeposition of lead dioxide was achieved in the presence of PVP on Pt and Ti substrates under constant current density from solutions containing Pb(NO3)(2) and NaF in HClO4. Scanning electron microscopy (SEM) showed that the morphology and particle size of PbO2 are strongly affected by the concentrations of Pb(NO3)(2), PVP and HClO4. It seemed that PVP can control both the morphology and particle size of lead dioxide and increases the overpotential for oxygen evolution during the electrodeposition of lead dioxide. The resulting lead dioxide was composed of nano-metric globular particles aligned in rice shaped structure with diameter in the range of 30-50 nm. It was suggested that the growth of PbO2 crystals is affected by the aqueous network of self-assembled surfactant formed on the electrode surface during the electrodeposition process. The electrochemical impedance spectroscopy (EIS) was used to investigate the interfacial behavior of deposited lead dioxide in 0.5 M H2SO4 solution. The EIS results revealed a typically porous electrode behavior consisted of a straight line, at high frequency region, turning to a potential dependent semicircle, at low frequency region, the diameter of which being decreased with increasing potential increments. The X-ray diffraction (XRD) patterns show that samples were composed of beta-PbO2. (c) 2007 Elsevier Ltd. All rights reserved.