Catalytic Growth of Structured Nitrogen-Containing Carbon over Unsupported and Y Zeolite Supported Ni and Co Catalysts
Advancing the chemical engineering fundamentals
Catalysis (T2-13P)
Keywords: Chemical Vapour Decomposition, Nickel, Cobalt, carbon growth
The discovery of structured carbonaceous materials with a diversity of unique chemical and physical properties has attracted a significant research effort focused on alternative syntheses and new applications in gas adsorption, H2 storage, and electronics. In addition, structured carbon has been used as catalyst support and as an electrochemical promoter in fuel cells. Doping these carbonaceous structures with heteroatoms, such as nitrogen or boron, is an effective means of modifying surface and electronic properties. Indeed, it has been established [1] that the incorporation of nitrogen in nanotubes results in enhanced conductivity, polarity and basicity while modifying surface hydrophilicity.
In earlier work, we reported the growth of structured carbon via the decomposition of ethylene over Y zeolite supported Ni [2,3] and recorded reproducible yields of uniformly sized carbon nanofibers. This work has since been extended to consider carbon growth over bulk and Y zeolite supported Ni and Co, using acetonitrile as the carbon precursor.
Carbon growth was carried out at atmospheric pressure in a continuous flow fixed bed catalytic reactor over the temperature range 550-1150 ºC with an inlet acetonitrile/metal ratio = 0.73 gC gmetal-1min-1, GHSV = 16000 h-1 and reaction time up to 60 min, which allowed for a uniform carbon growth. The solid carbon deposits have been characterized by BET, XRD, temperature programmed oxidation (TPO), TEM and CNH analyses.
In this presentation, the effect of temperature, reaction time and the nature of the active metal on carbon yield is considered, the role of the support is addressed and the structural diversity (morphology, aspect ratio and graphitic nature) of the carbon product is demonstrated. The viability of incorporating nitrogen in the carbon growth is also discussed.
References
[1] Maiyalagan, T.; Viswanathan, B. Template synthesis and characterization of well-aligned nitrogen containing carbon nanotubes. Mater. Chem. Phys 93 (2005) 291-295.
[2] De Lucas, A.; Garrido, A.; Sánchez, P.; Romero, A.; Valverde, J.L. Growth of carbon nanofibers from Ni/Y zeolite based catalysts: Effects of Ni introduction method, reaction temperature, and reaction gas composition. Ind. Eng. Chem. Res. 44 (2005) 8225-8236.
[3] Park, C.; Keane, M.A. Controlled growth of highly ordered carbon nanofibers from Y Zeolite supported nickel catalysts. Langmuir 17 (2001) 8386-8396.
Presented Wednesday 19, 13:30 to 15:00, in session Catalysis (T2-13P).
