Different cobalt containing materials obtained from the thermal decomposition of two organic precursors, cobalt-acetylacetonate, and cobalt-tetrametoxyphenylporphyrin, and CO3O4 prepared by thermal decomposition of cobalt carbonate have been characterised by thermogravimetric analysis (TGA), X-ray diffraction (XRD) and high resolution transmission microscopy (HRTEM). It has been found that the cobalt precursor, the organic macrocycle and the active carbon are simultaneously needed during the heat treatment in inhert atmosphere. Their contemporaneous presence is useful to obtain a material on which the dispersed metal is able to catalyse reactions that produce pores or tunnels inside the carbon, thus resulting in an enhanced contact area. The organic macrocycle is only partially decomposed and the residual fraction could enhance the conductivity. (c) 2005 Elsevier B.V. All rights reserved.