Novel catalysts were prepared from magnetic microspheres and cenosphere recovered from fuel ashes being formed in combustion of Irsha-Borodinskii lignite and Kuznetskii coal. The specific features of microsphere formation in the coal combustion were discussed. The morphology as well as composition of different magnetic microspheres and cenospheres were studied by SEM, electron probe microanalysis and Mossbauer spectroscopy. The morphology of globules, crystallite size and defect structure of active phase was established to depend on the basicity of the glass phase. It was shown that catalytic activity of magnetic microspheres and cenosopheres in the reaction of deep oxidation of methane is determined by the spinel phase and depends on the extent of its accessibility and type of defect structure. (C) 2001 Elsevier Science B.V. All rights reserved.