XPS characterisation of catalysts during production of multiwalled carbon nanotubes

Abstract

Characterisation of alumina supported catalysts was performed by TEM and XPS spectroscopy during formation of multiwalled carbon nanotubes from acetylene at 1000 K. TEM images showed that thick carbon fibres (outer diameter is around 20–40 nm) were generated on Fe/Al₂O₃ and Co/Al₂O₃ samples. The only sample producing carbon nanotubes with an average diameter of 8–12 nm was the bimetallic CoFe/Al₂O₃. XPS spectra revealed that Fe–Co alloy formed during the interaction of CoFe/Al₂O₃ and acetylene at 1000 K.