Direct synthesis of unimodal and bimodal nanoporous carbon

Unimodal and bimodal nanoporous (mesoporous) carbons have been synthesized by simply removing silica from carbon/silica nanocomposites. The sucrose/silica nanocomposites are directly prepared by the sol-gel process of tetraethyl orthosilicate (TEOS) with or without colloidal silica particles in the presence of carbon precursor molecules (i.e., sucrose). Subsequent carbonization converts the sucrose/silica nanocomposites into nonporous carbon/silica composites. Removal of the silica templates results in nanoporous carbons with high surface areas (e.g., > 1500 ml/g) and pore volumes (e.g., > 1.0 cm(3)/g). Using TEOS as the only silica source, nanoporous carbons with unimodal similar to2 nm worm-like pores are produced. Nanoporous carbons with bimodal similar to2 and similar to27 nm diameter pores have been prepared by using both the TEOS-derived silica network and the colloidal silica particles as templates. (C) 2004 Elsevier Inc. All rights reserved.