A COMPARATIVE-STUDY OF LACOO3, CO3O4 AND LACOO3-CO3O4 .1. PREPARATION, CHARACTERIZATION AND CATALYTIC PROPERTIES FOR THE OXIDATION OF CO

LaCoO3, Co3O4 and a mix of them, were synthesized and studied in the c ase of automotive exhaust reactions. Two preparation methods were used : simultaneous precipitation and a sol-gel type. The samples were char acterised by X-ray diffraction. TPR, TPO and microanalysis. The CO oxi dation reaction was performed under dry or wet atmospheres for a binar y CO+O-2 and a complete CO+NO+C3H8+O-2 gas mixture. In all cases, the cobalt oxide pointed out the best performances. A quenching effect of the surface of the sol-gel catalysts induced activity at room temperat ure under the CO+O-2 dry mixture, Under the complete wet gasmixture, t he perovskite LaCoO3 showed a lower activation energy for the CO oxida tion reaction than for Co3O4.