PYROLYZED MACROCYCLES ON HIGH SURFACE-AREA CARBONS FOR THE REDUCTION OF OXYGEN IN ALKALINE FUEL-CELLS

Polarization characteristics and preparation methods of double-layer porous gas diffusion electrodes on various carbon materials in alkaline fuel cells were investigated. The electrodes with active carbon carriers were catalyzed with cobalt/iron tetraphonylporphyrin or silver. These electrodes show a potential of -186 mV (versus Hg/HgO) at 1.0 A/cm2 when operated with oxygen at 40-degrees-C and 5 M KOH. Various techniques such as surface area measurements, scanning (SEM) and transmission (TEM) electron microscopy in combination with energy dispersive spectroscopy (EDS) and electron energy loss spectroscopy (EELS) were used to characterize the structure and morphology of the catalyst layer.