(362e) On the Anchoring and Modification of Co Particles for the Synthesis of Single Walled Carbon Nanotubes From CO
Cobalt metal is a good catalyst for CO disproportionation to Single Walled Carbon Nanotubes (SWNT) if particle size can be stabilized on the nm scale. With reaction temperature in the range of 500-1000°C, this requires a chemical bonding and/or occlusion of nm Co particles. We have developed a synthesis of Co-MCM-41 that incorporates Co+2 isomorphously for silicon that can be partially reduced allowing Co clusters to anchor to Co cations in the silica matrix, see S. Lim et al., Catal. Today, 123 (2007) 122. There are other ways that Co can be anchored, e.g., by interaction with Mo, see J. E. Herrera and D. E. Resasco, J. Catal., 221 (2004) 354. The use of structured silicas other than MCM-41, e.g., SBA-15 and silicalite, and in combination with Co-Mo interaction, to modify SWNT diameter distribution and yield will be presented. The method of preparation of Co-Mo/MCM-41, e. g., incorporation, impregnation or grafting of both Co and Mo in all combinations, can substantially affect Co-Mo interaction and, in turn, modify the yield and diameter distribution of SWNT. We seek a generalized model for the stabilization of nm Co particles against sintering under SWNT synthesis for CO under reaction conditions.