CCVD synthesis of carbon nanotubes with W/Co–MgO catalysts
Résumé
Carbon nanotubes (CNT) were synthesized from a H2–CH4 mixture with W/Co–MgO catalyst
by a catalytic chemical vapour deposition (CCVD) method. Different W/Co ratios were
investigated. From transmission electron microscopy observations, we observed that both
the number of walls and the diameter of CNT increased with the proportion of tungsten. A
promoter effect was observed as long as the proportion of tungsten was kept low and CNT
with a number of walls ranging from 2 to 5 were obtained. With a higher proportion of
tungsten, multi-walled carbon nanotubes (MWNT) up to 10 walls were synthesised,
together with additional undesirable carbon nanofibres.