Uniform synthesis of multi-walled carbon nanotubes in a stainless steel porous block

High purity multi-walled carbon nanotubes (MWCNTs) were synthesized on the inner surfaces throughout a porous stainless steel cube with a 1 cm side having pores of approximately 300 μm diameter. For this synthesis, the inner surface of the stainless steel block was activated by heat treatment in O2–Ar environment at 800 °C followed by reduction in H2–Ar at 700 °C. This was followed by diffusing a mixture of ethylene and Ar into the pores for the formation of the MWCNTs. It was confirmed that the structure and purity of the MWCNTs synthesized in this stainless steel block were uniform.