The sol-gel technique has been studied to fabricate a homogeneous Fe-Mo/MgO catalyst.
Ambient effects (air, Ar, and H2) on thermal decomposition of the citrate precursor have
been systematically investigated to fabricate an Fe-Mo/MgO catalyst. Severe agglomeration
of metal catalyst was observed under thermal decomposition of citrate precursor in air atmosphere.
Ar/H2 atmosphere effectively restricted agglomeration of bimetallic catalyst and formation
of highly-dispersed Fe-Mo/MgO catalyst with high specific surface-area due to the
formation of Fe-Mo nanoclusters within MgO support. High-quality thin-multiwalled carbon
nanotubes (t-MWCNTs) with uniform diameters were achieved on a large scale by catalytic
decomposition of methane over Fe-Mo/MgO catalyst prepared under Ar-atmosphere.
The produced t-MWCNTs had outer diameters in the range of 4-8 nm (average diameter
~6.6 nm) and wall numbers in the range of 4-7 graphenes. The as-synthesized t-MWCNTs
showed product yields over 450% relative to the utilized Fe-Mo/MgO catalyst, and indicated
a purity of about 85%.