Preparation of hierarchical porous biomorphic carbide-derived carbon by polycarbosilane impregnation of wood

Abstract

Biomorphic carbide-derived carbon (CDC) materials with hierarchical pore structure are prepared by polycarbosilane impregnation of carbonized wood monoliths followed by subsequent pyrolysis and high-temperature chlorine treatment. Hierarchical pore structures are generated with combined macropores from the original cell structure of the wood and micro-/mesopores, investigated by scattering electron microscopy and nitrogen physisorption, respectively. The influence of polycarbosilane solutions concentration (20–100 wt.%), impregnation time (12–96h), and impregnation cycle number (1–3 times) on the mass gain during impregnation as well as specific surface area and nanopore volume of resulting CDCs is studied. Increasing concentration, time, and number of impregnation cycles lead to higher amount of infiltrated polymer in the wood monolith resulting in higher specific surface areas up to 940m2/g for the resulting CDCs. A linear increase of specific surface area as well as micro- and total pore volume with increasing mass gain takes place for all samples, independent of the impregnation conditions.