Fe/Co Alloys for the Catalytic Chemical Vapor Deposition Synthesis of Single- and Double-Walled Carbon Nanotubes (CNTs). 2. The CNT−Fe/Co−MgAl2O4 System - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Physical Chemistry B Année : 2005

Fe/Co Alloys for the Catalytic Chemical Vapor Deposition Synthesis of Single- and Double-Walled Carbon Nanotubes (CNTs). 2. The CNT−Fe/Co−MgAl2O4 System

Résumé

A detailed 57Fe Mössbauer study of the Mg(0.8)Fe(0.2-y)Co(y)Al2O4 (y = 0, 0.05, 0.1, 0.15, 0.2) solid solutions and of the CNT-Fe/Co-MgAl2O4 nanocomposite powders prepared by reduction in H2-CH4 has allowed characterization of the different iron phases involved in the catalytic process of carbon nanotube (CNT) formation and to correlate these results with the carbon and CNT contents. The oxide precursors consist of defective spinels of general formulas (Mg(1-x-y)(2+)Fe(x-3alpha)(2+)Fe(2alpha)(3+)[symbol: see text](alpha)Co(y)(2+)Al2(3+))O4(2-) . The metallic phase in the CNT-Fe/Co-MgAl2O4 nanocomposite powders is mostly in the form of the ferromagnetic alpha-Fe/Co alloy with the desired composition. For high iron initial proportions, the additional formation of Fe3C and gamma-Fe-C is observed while for high cobalt initial proportions, the additional formation of a gamma-Fe/Co-C phase is favored. The higher yield of CNTs is observed for postreaction alpha-Fe(0.50)Co(0.50) catalytic particles, which form no carbide and have a narrow size distribution. Alloying is beneficial for this system with respect to the formation of CNTs.
Fichier principal
Vignette du fichier
coquay_10384.pdf (236.29 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03599613 , version 1 (07-03-2022)

Identifiants

Citer

Pierre Coquay, Emmanuel Flahaut, Eddy de Grave, Alain Peigney, Robert E. Vandenberghe, et al.. Fe/Co Alloys for the Catalytic Chemical Vapor Deposition Synthesis of Single- and Double-Walled Carbon Nanotubes (CNTs). 2. The CNT−Fe/Co−MgAl2O4 System. Journal of Physical Chemistry B, 2005, 109 (38), pp.17825-17830. ⟨10.1021/jp052494y⟩. ⟨hal-03599613⟩
7 Consultations
8 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More