High aspect ratio (>5000) composite with macroscopic shape consisted of multi-walled carbon nanotubes bridging a 3D network of the micrometers carbon felt host structure was synthesized by means of the chemical vapour deposition technique. Such carbon-based nano-macro composite material displays a high mechanical strength, high electrical conductivity along with a high and fully accessible effective surface area (>100 m(2) g(-1)), which allows it to be efficiently employed as structured catalyst support, in fixed-bed catalytic reactions, without the problem of pressure drop as encountered with the nanoscopic carbon support materials. The nanoscopic structure also provides a high degree of mixing of the reactant mixture which strongly increases the effective surface contact between the reactants and the active sites. In addition, the total effective surface area of the composite can be finely tuned, depending to the downstream application, as a function of the carbon nanotubes intake. (C) 2010 Elsevier B.V. All rights reserved.