Synthesis of high density 4 A single-walled carbon nanotubes in AlPO4-5 zeolites

The effect of carbon precursors on the formation of 0.4 nm single-walled carbon nanotubes (SWNTs) in one-dimensional channels of AlPO₄-5 single crystals was studied by means of Raman spectroscopy. Among more than ten carbon precursors which can be used in the fabrication of 0.4 nm SWNTs in the channels, the precursor of tetrapropylammonium-hydroxide (TPAOH) molecule not only contains rich carbon atoms, but also well fits to the unit cell of the AlPO₄-5 framework. Thus, the loading density of TPAOH carbon precursor inside the channels of AlPO₄-5 crystals is much more than other ones. The resulting SWNTs have higher filling density in the channels and have a better quality than those fabricated using other carbon precursors, as evidenced by the intensive Raman signals in the radial-breathing modes