Ni/CFC catalysts were shown to have sufficient efficiency in secondary carbon formation in low-temperature methane decomposition (525 degrees C). The highest yield of secondary carbon was found to reach 268.5 g/g(Ni) on Ni/CFC (Fe-Ni) catalyst. The catalytic properties of Ni/CFCs may be explained by formation of active Ni particles (ca. 50 nm in size), which are optimal for growth of filament with "herring-bone" structure. The large Ni particles are preferably localized in the pores formed by interlaced filaments and the interaction of metal particles with graphene basal planes occurs mainly through weak dispersive forces. The accumulation of carbon on Ni/CFC catalysts is also influenced by textural properties of the used supports. The carbon supports with high value of the meso- and macropore volume are likely to be more suitable for development of Ni/CFC catalysts for low-temperature methane decomposition. The modification of the textural properties of catalytic filamentous carbon (CFC) by their activation with H(,)2or CO2 opens up interesting possibilities of its application as support in heterogeneous catalysis. (c) 2005 Elsevier B.V. All rights reserved.