Solid solutions of LaMxFe1−xO3 (with M = Ni and Co) have been used in the Fischer- Tropsch reaction (CO + H2 → Hydrocarbons + CO2) and in the partial oxidation of methane (CH4 + 1/2 O2 → CO + 2 H2). In both catalytic reactions, the active catalyst is reported to be reduced metal particles; their size and their interactions with the support induce large differences in the product distribution.
In the nickel system, after total reduction by TPR all catalysts exhibit ferromagnetic behavior at room temperature. In situ magnetization in 1 Tesla on cooling the sample under reducing atmosphere shows one magnetic transition for each sample indicating one Curie temperature. These Curie temperatures are in between those known for bulk nickel and iron and decrease with the initial nickel content of the perovskite. This indicates that nickel is reduced first and induces the reduction of iron, leading to the formation of an alloy.
In the cobalt system, in situ magnetization on heating the sample shows a sharp increase of the magnetization only for x = 0.25, 0.40 and 1, corresponding to the formation of metallic cobalt nanoparticles. All other materials present only one increase of the magnetization for temperatures similar to those observed for the second reduction in TPR corresponding to the formation of CoFe alloys.