TRANSITION-METAL MIXED OXIDES AS COMBUSTION CATALYSTS - PREPARATION, CHARACTERIZATION AND ACTIVITY MECHANISMS

A number of transition metal mixed oxides with spinel-type, corundum-t ype and perovskite-type structures have been prepared and characterize d. Attempts have been made to improve their morphological properties a nd their stability. Some of them have been tested in the catalytic com bustion of methane, CO and H-2 (perovskites), of propane and of phenan trene. FT-IR experiments allowed to obtain a quite complete picture of the mechanism of catalytic combustion of C3 organic compounds on spin el-type oxides MgCr2O4 and Co3O4. Nucleophilic oxygen species (lattice oxygen) is thought to be involved in both partial and total oxidation .