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 ar e metal oxides has been also investigated and produced active electrocataly tic materials for the oxygen evolution reaction (OER). The structure of some composites with PbO2 as the matrix and in which the d ispersed phase is an oxide (Fe2O3, Bi2O3, SnO2) have been prepared and char acterised by SEM pictures, EDX and atomic absorption measurements. The reac tivity of the PbO2/Fe2O3 electrode for the OER has been pointed out with ov ervoltage measurements and Tafel plots in a solution of Na2SO4 0.5M pH=7. T he 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 propor tionally reduced by increasing the amount of the incorporated Fe2O3.