Novel catalysts for carbon nanotube and nanofibre synthesis
2009 (English)Conference paper, Presentation (Refereed)
Carbon nanotubes are of huge interest to the scientific community for their physical and electronic properties. We have synthesized carbon nanotubes (CNTs) on novel non-traditonal catalysts. Bamboo-shaped carbon nanotubes (BCNTs) were synthesized on Pd and Cu catalysts doped with either Mo or W. BCNTs were sythesised using the catalytic chemical vapour decomposition (CVD) of methane. Cu is catalytically inactive for the synthesis of CNTs; however this is not the case when Cu is doped with Mo and W. When Cu is doped with these metals bamboo structured CNTs can be produced via a CVD synthesis method. The addition of a dopant alters the electronic structure of catalyst nanoparticle causing the binding strength between the nanoparticle and carbon to approach that of traditional catalysts for CNT growth i.e. Fe; Co; Ni and their alloys which has been shown by computer modeling. We have performed full geometry optimization DFT calculations of Cu/W and Pd/Mo particles of different compositions to determine their ability to stabilize and support the growing end of a CNT. We have computed a (5;0) SWNTs binding energy to a M13 metal cluster (M=Cu; W or Pd; Mo); which in a model system that has been proven to correctly predict the trends in bonding[2; 3]. The resulting binding energies are compared to Fe; Co; Ni and Cu/Mo clusters of these previous reports. All calculations were made using the generalized gradient approximation (GGA) exchange and correlation potential by Perdew-Burke-Ernzenhof [PBE]; utilizing the polarized valence triple-ζ (TZVP) basis set and relativistic effective core potentials (ECPs) for Cu; Pd; W and Mo[5; 6]; as implemented in the Turbomole suite of programs[7-10].
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IdentifiersURN: urn:nbn:se:ltu:diva-35617Local ID: a393a2fa-7a91-41c1-9591-6a4c1ca75b75OAI: oai:DiVA.org:ltu-35617DiVA: diva2:1008870
MRS Spring Meeting & Exhibit : 14/04/2009 - 17/04/2009
Upprättat; 2009; 20130409 (andbra)2016-09-302016-09-30Bibliographically approved