Carbon nanostructures, nanofibers and nanotubes, with a I D dimension have witnessed, during the last decade, a large scientific and industrial interest owing to their exceptional physical and chemical properties. Among the different potential applications the use of these carbon nanostructures as catalyst support material seems to be one of the most promising. In the present work, the synthesis and characterisation of a new type of carbon nanofibers (CNF) composite with macroscopic shaping is reported. The CNF composite obtained can be tailored into different macroscopic shapes allowing it to be directly employed in the existing conventional reactors without the problems linked to the small size of the unsupported carbon nanofibers. This material displays a relatively high surface area > 100 m(2) g(-1), essentially constituted by the external surface, and a complete absence of the bottled pores encountered with traditional solid carriers such as alumina, silica or activated charcoal. The as-synthesized CNF composite was subsequently tested as catalyst support in two reactions, i.e. the catalytic decomposition of hydrazine and the selective oxidation of H2S into elemental sulfur, where its catalytic performance was largely superior to that obtained on the state-of-the-art traditional catalysts. (c) 2005 Elsevier B.V. All rights reserved.