Preparation and Application of Nanostructured Perovskite Phases

Transition metal oxide compounds with perovskite‐type structure (AMX 3‐δ ) show besides attractive physical properties, such as high temperature superconduction or thermoelectricity, often excellent catalytic properties for various redox reactions. The catalytic reactivity is strongly dependent on composition, structure and of course the specific surface area of the compounds. Fine‐tuning of the properties can therefore be achieved by suitable cation‐ and anion‐ substitutions and by adjusting the morphology of the compounds. For systematic studies on the relationship between composition, structure and properties in these systems fine particles as well as thin films of identical compositions e.g. La 1‐x Ca x MO 3‐δ (x = 0, 0.3, 0.4 , 0.5) (M = Fe, Co, Ni, Mn, Ti) are produced with diverse “chimie douce” methods. The samples are characterised concerning their chemical and physical properties. Carbon nanotube composite materials have been produced by catalytic decomposition of gaseous carbon compounds on nanometer‐size transition metal clusters on top of perovskite‐type metal oxides and tested for a possible application as oxygen electrodes in air based batteries.