Electrochemical properties, composition and structure of lead dioxide-matrix composites.

Electrodeposition of metal-matrix composite materials has been extensively studied for increasing mechanical properties. Recently, the preparation of oxide-matrix composites in which both the matrix and the dispersed phase are metal oxides has been also investigated and produced active electrocatalytic materials for the oxygen evolution reaction (OER). The structure of some composites with PbO2 as the matrix and in which the dispersed phase is an oxide (Fe2O3, Bi2O3, SnO2) have been prepared and characterised by SEM pictures, EDX and atomic absorption measurements. The reactivity of the PbO2/Fe2O3 electrode for the OER has been pointed out with overvoltage measurements and Tafel plots in a solution of Na2SO4 0.5M pH=7. The pure PbO2 electrode has been compared with the PbO2/Fe2O3 Ones when the volume fraction of the dispersed phase Fe2O3 (alpha) increases. Our results have shown that PbO2/Fe2O3 composites are more active electrode materials for the OER then PbO2, the oxygen evolution overvoltage (etaO(2)) is proportionally reduced by increasing the amount of the incorporated Fe2O3.