XPS characterisation of catalysts during production of multiwalled carbon nanotubes

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.