Potentiality of Cobalt Nanoferrites for Gas Sensors

The catalytic effect of cobalt ferrites CoxFe3-xO4 nanopowders on the conversion of CH4 into CO2 was evidenced. The potentiality of acetylacetonate precursor solution for the elaboration of CoFe2O4 thin films was proven. The acetylacetonates precursor solution was fully characterized. Germs of crystallites, embedded in an amorphous phase, already exist in drops of the precursor solution. Dried at 210 degrees C, the solution led to 5 nm nanocrystallites with the cobalt ferrite spinel structure. In situ X-rays diagram showed that one can improve the crystallinity by annealing the powder or the films at only 500 degrees C. The films obtained by spin coating are patterned at a microscopic scale, with pavement of nanocrystallites 11 nm in size.