Highly porous S-doped carbons

Porous sulphur-doped carbons have been prepared by using polythiophene (PTh) as carbon precursor and KOH as activating agent. The activation process was carried out under several operating conditions, i.e. a KOH/PTh weight ratio of 2 or 4 and reaction temperatures in the 600-850 degrees C range. The porous carbons thus obtained exhibit very large apparent surface areas and high pore volumes of up to 3000 m(2) g(-1) and 1.75 cm(3) g(-1) respectively for a sample prepared at 850 degrees C and with a KOH/PTh weight ratio = 2. The pore size distribution of these carbons gradually changes with the reaction temperature. Thus, whereas the porosity of the samples prepared at 600 C is mostly formed by micropores similar to 1 nm, those obtained at 850 degrees C exhibit two pore systems with diameters of similar to 1 nm and similar to 2.5 nm. These polythiophene-based porous carbons have large sulphur contents in the 3-12 wt% range, and this percentage decreases as the reaction temperature rises. The sulphur present in these carbons forms two types of functional groups (i.e. sulphide -C-S-C- and sulphone -C-SO2-C-) which act as bridges between adjacent aromatic rings. (C) 2012 Elsevier Inc. All rights reserved.