Carbon Nanotube Synthesis Using Mesoporous Silica Templates

Abstract

Well-aligned carbon nanotubes (CNTs) were grown on mesoporous silica films by chemical vapor deposition (CVD). Ethylene was used as the carbon source and CVD was performed at 1023 K and atmospheric pressure. The films were doped with Fe during sol−gel synthesis, and three different structure directing agents were used for mesoporous silica preparation: polyoxyethylene (10) cetyl ether (C16EO10), Pluronic tri-block copolymer (P123), and cetyltriethylammonium chloride (CTAC). A high degree of CNT alignment on C16EO10 mesoporous silica films was produced at Fe:Si molar ratio of 1.80. Similar alignment of CNTs was achieved in the other preparations, but on CTAC-derived films CNTs only grew parallel to the substrate surface because the in-plane arrangement of the pore structure limited CNT growth to crack domains. We also show that the diameter of the CNTs can be controlled by changing the Fe concentration in the mesoporous silica substrate.