(490i) Molecular Modeling and Adsorption Properties of Silica Templated Mesoporous Carbons

Mesoporous carbons with highly ordered pore structures can be obtained by templating ordered silica materials. These carbons offer high mechanical and thermal stability and are useful in many applications including adsorption of large molecules, catalyst in fuel cells and capacitor electrodes. Many experimental studies have been reported on obtaining carbon replica using different templating materials like SBA-15, MCM-41, Zeolites etc. The formation of these templated carbons is a two fold process [1]. A carbon rich precursor in vapor or liquid phase is first deposited inside the porosity of the matrix template. The adsorbed precursor is then carbonized by heating at a high temperature in an oxygen free environment to produce a carbon-matrix composite. Finally, the matrix is removed by treating with an acid and the carbon replica is obtained.

In this work, we present molecular models for two types of mesoporous carbons, CMK-3 [2] and CMK-5 [3], using pseudo mimetic methods. CMK-3 is obtained by templating SBA-15 in which carbon is infiltrated in the total porosity of SBA-15. It consists of carbon rods arranged in a hexagonal order and these carbon rods are held together via small interconnections. CMK-5 is obtained by templating SBA-15 in which carbon is introduced as a film on the pore surface of SBA-15. It consists of carbon pipes arranged in a hexagonal order and these carbon pipes are held together via small interconnections. We use these models of mesoporous carbons to study the adsorption behavior of argon using grand canonical Monte Carlo simulations. We investigate the effect of pore size and the role of interconnections between the carbon rods and pipes on the adsorption phenomenon of CMK materials.

[1] Ryoo, R.; Joo, S. H.; Jun, S. J Phys Chem B 1999, 103, 7743.

[2] Jun, S.; Joo, S. H.; Ryoo, R.; Kruk, M.; Jaroneic, M.; Liu, Z.; Ohsuna T.; Terasaki, O. J Am Chem Soc 2000, 122, 10712.

[3] Joo, S. H.; Choi, S. J.; Oh, I.; Kwak, J.; Liu, Z.; Terasaki, O.; Ryoo, R. Nature 2001, 412, 169.