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

Chemical activation of resorcinol-formaldehyde aerogels with phosphoric acid results in materials containing both intra-particle microporosity (pore volume similar to 0.18 cm(3)g(-1) and mean-pore-width similar to 1 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 cone trolled 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 cm(3)g(-1) with pore widths up to similar to 7 nm. Over 90% of these pores were accessible even after blocking all of the ultramicroporosity by pre-adsorption of n-nonane. (C) 2009 Elsevier Ltd. All rights reserved.