004 Influence of the Catalyst Hydrogen Pretreatment on the Growth of英文教材.pdf

Chem. Mater. 2007, 19, 6131–6137 6131 Influence of the Catalyst Hydrogen Pretreatment on the Growth of Vertically Aligned Nitrogen-Doped Carbon Nanotubes P. Ayala,*,†,‡ A. Grüneis,† T. Gemming,† B. Büchner,† M. H. Rümmeli,†,§ D. Grimm,† J. Schumann,† R. Kaltofen,† F. L. Freire Jr.,‡ H. D. Fonseca Filho,‡ and T. Pichler† Leibniz Institute for Solid State and Materials Research Dresden, P.O. Box 270116, D-01171 Dresden, Germany, Departamento de Fisica, Pontifícia UniVersidade Católica do Rio de Janeiro, 22453-900 Rio de Janeiro, Brazil, and Institute of Chemical and EnVironmental Engineering, Szczecin UniVersity of Technology, 70-322 Szczecin, Poland Recei Ved June 11, 2007. ReVised Manuscript ReceiVed September 18, 2007 Thin vertically aligned N-doped nanotubes with narrow layered nanotube diameter distribution and a defined doping level have been synthesized by chemical vapor deposition. Multilayered catalysts and a pure acetonitrile C/N feedstock have been employed. The observed nitrogen content was up to 6% with a predominant sp2 bonding configuration in relation to other nitrogen incorporated forms. Depending on the process parameters, we were able to tune the nitrogen content and the formation ratio of small nanotubes to bamboo nanotubes. The use of multilayer catalyst allows a large temperature window in which substitutionally doped structures form in comparison to other catalysts. 1. Introduction N-doped nanotubes are formed but also a clear determination