On the mechanism of carbon nanotube formation: the role of the catalyst

Abstract

This work examines the recent developments in non-traditional catalyst-assisted chemical vapour deposition of carbon nanotubes (CNTs) with a view to determining the essential role of the catalyst in nanotube growth. A brief overview of the techniques reliant on the structural reorganization of carbon to form CNTs is provided. Additionally, CNT synthesis methods based upon ceramic, noble metal, and semiconducting nanoparticle catalysts are presented. Experimental evidence is provided for CNT growth using noble metal and semiconducting nanoparticle catalysts. A model for CNT growth consistent with the experimental results is proposed, in which the structural reorganization of carbon to form CNTs is paramount.

Co3O4@Co/NCNT Nanostructure Derived from a Dicyanamide‐Based Metal‐Organic Framework as an Efficient Bi‐functional Electrocatalyst for Oxygen Reduction and Evolution Reactions

“…Notable differences were observed between Co/NCNT‐Ar, Co/NCNT‐H 2 , and Co 3 O 4 @Co/NCNT, clearly demonstrating that the pyrolization atmosphere plays a significant role in the catalytic nanostructure formation. The growth of NCNTs are favored due to the catalytic effect of in situ formed Co nanoparticles ,. Notably, the surface area of Co 3 O 4 @Co/NCNT is higher than Co/NCNT‐Ar and Co/NCNT‐H 2 catalysts prepared in this work.…”

Simulations of the synthesis of boron-nitride nanostructures in a hot, high pressure gas volume

“… 16 A significant difference between the production of a single-walled BNNT (SWBNNT) and their carbon SWCNT analogues is that no metal or other catalyst is needed for the BNNT synthesis. 17 In the case of SWCNT synthesis, a transition metal catalyst is usually required to drive the production of single-walled nanotube structures, unless CVD synthesis is performed under special conditions on a substrate 18 or from a seed template. 19 Nevertheless, similar to the case of carbon nanostructures, 20 the nucleation and growth mechanism of 0D nano-cocoons and nanocages, 1D BNNTs, and 2D h-BN flakes, is still under debate.…”

Photo-induced ignition phenomenon of carbon nanotubes by Xenon pulsed light: Ignition tests analysis, automotive and new potential applications, future developments

“…Finally, a further innovative application, concerning the automotive field, is related to the periodic clean of catalytic exhausts of vehicles. The operating of a catalytic converter is very similar to that of high pressure carbon oxide process (HiPCo), method used by industries for producing CNTs; hence, the formation of CNTs (both SWCNTs and MWCNTs) could occur in the honeycomb structure of the catalyst (Ayre et al, 2011;Deng et al, 2016;Pander, Hatta, & Furuta, 2016;Rümmeli et al, 2011). Furthermore, the metal nanoparticles, essential for obtaining the photo-ignition, can be added to those already present (i.e.…”