(36a) A General Approach Towards Hierarchical Carbon Particles

Porous carbon materials with high surface areas and large pore volumes are of great interest due to their potential applications as adsorbents, fillers, catalysts, electrodes, and hydrogen storage systems. In this study, spherical carbon particles with unimodal and bimodal nanoporous channels are synthesized from solutions of carbon precursors (i.e. sucrose), silica sols, and/or colloidal silica particles using a direct one-step aerosol process followed by carbonization and the removal of silica template. The resulting porous carbon particles show very high porosity with narrow pore size distributions, surface areas as high as 2000 m2/g, and pore volumes as large as 4 cm3/g. Using TEOS as the only silica source, nanoporous carbon particles with unimodal pores are produced. Using both TEOS and colloidal silica particles as templates, bimodal nanoporous carbon particles have been prepared. Foam-like highly porous carbon particles have been fabricated by using colloidal silica particles as the only template. The pore size and porosity can be adjusted by the type and amount of the colloidal silica particles. The porous carbon particles are characterized using transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), and nitrogen sorption techniques. The hydrogen adsorption abilities of these spherical porous carbon particles were investigated.