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 °C range. The porous carbons thus obtained exhibit very large apparent surface areas and high pore volumes of up to 3000 m2 g−1 and 1.75 cm3 g−1 respectively for a sample prepared at 850 °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 ∼1 nm, those obtained at 850 °C 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–C– and sulphone –C–SO2–C–) which act as bridges between adjacent aromatic rings.

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► Polythiophene was used as precursor to fabricate S-doped porous carbons.
► Highly microporous carbons with a surface area up to 3000 m2 g−1 were prepared by chemical activation with KOH.
► The carbon samples contains a high content of sulphur (up to 8.5%) which is forming bridges between the aromatic rings.