Fe- or Fe oxide-embedded anodic alumina membrane for nanocarbon growth―fabrication of membrane and observation of initial nanocarbon growth

•Fe- or Fe oxide-embedded freestanding anodic alumina membrane.•Very high-aspect-ratio nanoholes were filled by using atmospheric CVD.•Developed for continuous nanocarbon growth.

The present paper investigates the development of a novel process for fabricating catalyst membranes for a carbon transmittance method (CTM). The CTM is a continuous growth method for carbon nanotubes (CNTs) in which one chamber containing carbon source gas and another chamber filled with an inert gas for CNT growth are separated by a catalyst-embedded membrane. In the present study, the membranes were fabricated by filling the nanopores of a self-supporting anodic alumina membrane (AAM) with chemical-vapor-deposited Fe using Fe(CO)5 as a precursor. Nanocarbon (NC) was grown by a (non-CTM) catalytic chemical vapor deposition (CCVD) method, which is a standard technique for CNT growth, at 700 °C using C2H2 as a carbon source. The embedded Fe was oxidized during the temperature ramp prior to C2H2 addition, whereas the oxidized Fe functioned as a catalyst for NC growth. When the pores of the AAM were filled with Fe oxide, the fill Fe oxide functioned as a good catalyst.

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