ON THE RELATIONSHIP BETWEEN THE SOLID-STATE PHYSICOCHEMICAL CHARACTERISTICS AND THE HETEROGENEOUS ELECTROCATALYTIC ACTIVITY OF LANTHANUM MANGANATES FOR OXYGEN REDUCTION IN ALKALINE FUEL-CELLS

Lanthanum manganates are prepared in different nonstoichiometric compo sitions through solid state sintering technique. The physicochemical d ata like apparent density, specific resistivity, specific surface area and particle size distribution of these oxides are obtained. The elec tron spectroscopic chemical analysis (ESCA) characteristics of these o xides are reported. The XRD patterns of these oxides are presented. A brief discussion on the application of these oxides as electrocatalyst s in the fuel cell cathodes to relate their solid state physicochemica l characteristics with their electrochemical activity is attempted. It is concluded that the solid state reactivity of these oxides in the r eduction of molecular oxygen for their application in fuel cells is go verned by the combined influence of both their bulk and surface proper ties.