(224e) The Synthesis of Swnt Supported Co Catalyst and Comparison with MCM-41 Supported Co
Co-MCM-41 (Co incorporated isomorphously for Si in MCM-41 during synthesis) has proven to have superior stability for the high temperature catalytic synthesis of single walled carbon nanotubes (SWNT). With the availability of high quality < 1nm diameter SWNT, SWNT may be investigated as a catalytic support. SWNT as a support has been shown to have advantages with respect to stability, activity and selectivity for reactions involving hydrogen. The Co-SWNT was produced during SWNT synthesis using Co-MCM-41 as catalyst by dissolution of the silica matrix in dilute NaOH. Methanation was used as a new approach to clean the cobalt particles which are covered by amorphous carbon, as well as by graphite and/or surface carbide, but only the amorphous carbon can be removed by methanation without consumption of SWNT per se. From temperature programmed methanation of Co-SWNT, from which the silica matrix has been removed, different carbon states may be identified by the difference of methanation temperature and the temperature of methanation adjusted to avoid methanation of SWNT. Carbon monoxide methanation was chosen as the probe catalytic reaction to compare the SWNT supported Co catalyst with well defined Co incorporated MCM-41 and Co impregnated MCM-41. A second probe reaction for which SWNT may be an excellent support is for the low temperature aqueous reforming of oxygenated hydrocarbons which will be chosen by screening with the CO methanation reaction.