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Nitrogen adsorption studies have been employed to examine the structural properties of micro-/meso-porous carbons obtained by colloidal templating and post-synthesis KOH activation. These carbons were prepared by polymerizing phenol and formaldehyde in the pores of a colloidal silica template followed by carbonization, silica dissolution and post-synthesis KOH activation. Colloidal silica was used to create spherical mesopores, while KOH activation was performed to create additional microporosity and to enlarge the surface area of the resulting carbons. Nitrogen adsorption studies showed that a single impregnation of the colloidal silica template with phenolic resin precursors afforded carbons with relatively thin pore walls which did not withstand the post-synthesis KOH activation; however, a double impregnation generated mesoporous carbons with thicker pore walls. Activation of these latter carbons with KOH created micropores in the mesopore walls without significant deterioration of the mesopore structure. The resulting mesoporous carbons possessed high specific surface areas (ca. 800 m2/g) and large single-point pore volumes (ca. 1.8 cm3/g). The post-synthesis KOH activation enlarged the surface area up to 1500 m2/g, which was achieved via the creation of microporosity. Hence, the carbon obtained by double impregnation and activation exhibited a single-point pore volume of ca. 2 cm3/g with a relatively high microporosity which attained 17% of the total porosity. High-surface-area micro-/meso-porous carbons are attractive for adsorption, catalysis and energy-related applications such as capacitors and batteries. [ABSTRACT FROM AUTHOR]

Abstract: A series of mesoporous carbons with high loading of silica has been synthesized by acid-catalyzed polymerization of resorcinol and formaldehyde in the presence of tetraethyl orthosilicate (TEOS), colloidal silica (silica source) and poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) triblock copolymer (soft template) followed by carbonization. This synthesis route can be considered as a combination of soft-templating and hard templating strategies. The resulting mesoporous silica–carbon composites contained spherical silica colloids in addition to uniformly distributed silica originated from TEOS. Dissolution of silica led to high surface area carbons, which in addition to the primary mesopores formed by thermal degradation of block copolymer template possessed spherical mesopores after dissolution of silica colloids and fine pores after removal of TEOS-generated silica species. This approach can be used to incorporate other inorganic nanoparticles into mesoporous carbons with extra microporosity created after dissolving TEOS-generated silica species. [Copyright &y& Elsevier]