Textural characterization of self-oriented multi-walled carbon nanotubes arrays by gas adsorption measurements

D. ZILLI; A. L. CUKIERMAN; S. BLACHER; C. J. GOMMES; J. P. PIRARD

Nancy, Francia

Congreso; Lignocarb Conference; 2007

ALFA EUROPEAID CO-OPERATION OFFICE, NANCY-UNIVERSITÉ, ENSTIB

Self-oriented multi-walled carbon nanotubes (CNTs) assemblies were lab-synthesized in PINMATE (Argentina) by in situ catalytically chemical vapour deposition (CCVD) of an organo-metallic compound for different sets of operating conditions, including variation of the reaction temperature, H2 molar fraction, gaseous flow rate, and/or reaction time. The morphological features of the individual CNTs building the assemblies were characterized by transmission electron microscopy (TEM). TEM micrographs showed the presence of many Y-junction-like structures self-grown in the CNTs assemblies. Figure 1 illustrates some of the Y-junctions observed, for example. The outer diameter distributions of those samples showing Y-junctions were measured. The histograms are found to be bimodal, one mode corresponds to the two branches of the Y, whereas the other mode corresponds to its main trunk. According to TEM pictures, the orientation of the concavity of inner structures of the nanotubes shows unambiguously that the observed Y-junctions are formed by the merging of metal nanoparticles during the growth of the individual CNTs constituting the assemblies.