New carbon materials with high porosity in the 1–7 nm range obtained by chemical activation with phosphoric acid of resorcinol–formaldehyde aerogels

Abstract

Chemical activation of resorcinol–formaldehyde aerogels with phosphoric acid results in materials containing both intra-particle microporosity (pore volume ˇ0.18 cm3g 1 and mean-pore-width ˇ1 nm) and inter-particle micro/mesoporosity. The latter forms as a result of partial collapse of the mesopore structure of the organic aerogel and can be controlled by varying the phosphoric acid/organic aerogel ratio. Increasing this ratio leads to higher pore volume and size and it was possible to obtain micro/mesopore volumes as high as 1.23 cm3g 1 with pore widths up to ˇ7 nm. Over 90% of these pores were accessible even after blocking all of the ultramicroporosity by pre-adsorption of n-nonane.