Catalytic reactivities of Ni-Fe oxides (atomic ratio of Ni to Fe is 1) prepared by coprecipitation and by physical mixing have been investigated in order to use such oxides in the synthesis of phenol from benzoic acid. It was found that the phenol yield of the oxide prepared by coprecipitation was 3 to 5 times higher than that prepared by physical mixing. Microstructures of these oxides have been studied by analytical electron microscopy (AEM). We found that only for the oxide prepared by coprecipitation about a half of catalyst particles exists as complex particles in which the NiO and NiFe2O4 particles have a coherent relationship. This epitaxial structures might play an important role in the higher catalytic activity of the oxide for phenol synthesis.
