ELECTROCHEMICAL CHARACTERIZATION AND MORPHOLOGICAL-STUDIES OF PALLADIUM-MODIFIED CARBON CERAMIC ELECTRODES

Palladium-modified carbon ceramic composite gas electrodes (Pd/CCE) ar e presented and characterized. The electrodes are comprised of graphit e powder percolating through hydrophobically modified silica xerogels. The electrodes were prepared by mixing Pd salt and carbon powder with the sol-gel precursors and reduction of palladium ions after xerogel formation. The morphology and surface characteristics of the composite materials were examined by electron microscopy, X-ray microanalysis, nitrogen adsorption and water wetting angle measurements. Oxygen reduc tion was used as a model reaction to probe the characteristics of the wetted section of the Pd/CCEs. Voltammetric studies and polarization c urves were employed to elucidate the size and structure of the active layer as a function of palladium content.