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 oC range. The porous carbons thus obtained exhibit very large apparent surface areas and high pore volumes of up to 3000 m⋅g and 1.75 cm⋅g respectively for a sample prepared at 850 oC 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 oC is mostly formed by micropores ~1 nm, those obtained at 850 oC exhibit two pore systems with diameters of ~1 nm and ~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-Cand sulphone -C-SO2-C-) which act as bridges between adjacent aromatic rings.