(588e) Reverse Templating of Mesoporous Ceramics to Produce Highly Porous Structured Carbons From Sugars

Authors: 
St.Dennis, J., Tulane University
Venkataraman, P., Tulane University
Sunkara, B., Tulane University
John, V. T., Tulane University
McPherson, G. L., Tulane University
He, J., Tulane University
Jones, C. Y., Hamilton College
Obrey, S. J., Los Alamos National Laboratory
Currier, R. S., Los Alamos National Laboratory
Bose, A., University of Rhode Island


Novel carbon materials, such as nano-tubes, fullerenes and uni-dimensional structures, have received significant attention in recent years due to their applications in gas storage, catalysis, and in electrochemical devices (supercapacitors and electrodes). We describe here methods to use sugars as precursors to produce a variety of nanostructured carbons using the reverse template of porous titanias and silicas. These templates are prepared from surfactant mesophases that exhibit long range crystallinity and exist as stable gels. In particular, we focus on the 2-D hexagonal mesophase templates formed using the twin-tailed anionic surfactant bis(2-ethylhexyl) sodium sulfosuccinate (AOT) and the zwitterionic surfactant phosphatidylcholine (lecithin). These materials exhibit the characteristics of a rigid gel and maintain initial structural integrity when used as templates for the synthesis of ceramics such as silica and titania. The templated ceramics exhibit a hierarchical pore structure where 10 nm pores evolve to 200 nm pores. We then use these ceramics as templates by infiltrating carbon precursors, forming carbons through pyrolysis and then etching away the ceramic. The resultant carbon materials exhibit the inverse pore structure and long range order of the template. High resolution electron microscopy is used to understand the evolution and growth of these carbon structures. Variations of carbon structure and morphology develop upon changing the carbon precursor from sucrose to the cyclodextrins to a polysaccharide (carboxymethyl cellulose). The role of ?threading? cyclodextrin to form templated carbons will be described.