Keywords: N, S co-doped

Herein, we have produced two series of novel materials including heteroatoms-doped (thiourea-modified) and heteroatoms-deprived microporous carbons using three different potassium salts activators (KOH, K2CO3, K2C2O4). The experimental results reveal that thiourea-modified KOH activated sample exhibit excellent textural features (specific surface area-1795 m2/g, micropore volume-0.82 cm3/g) but at the expense of a reduced heteroatom content. However, sample prepared with K2C2O4 exhibited a comparable specific surface area (-1747 m2/g), enough population of narrow micropores (<1.0 nm), the highest micropore volume (0.93 cm3/g) and a high nitrogen (4.6 at. %) and sulfur content (2.3 at. %). Therefore, the optimized sample, STO, exhibits remarkable CO2 adsorption (269.61 mg/g at 0 C and 1 bar), excellent IAST CO2/N2 selectivity (73), high isosteric heat of adsorption (39.3 kJ/mol) and high cyclic stability, surpassing the CO2 adsorption/separation performance of most of the biomass-derived carbons. Herein, for the first time, a comprehensive study on potassium salts activation, in comparison with the conventionally practiced KOH activation, is presented. Concluding, the experimental results unveiled K2C2O4 as a more competitive and less corrosive potassium salt activating agent by virtue of its ability to fabricate N, S dual-doped highly porous carbons for efficient CO2 adsorption and separation.

Automated summary

The research demonstrates that samples activated with K2C2O4 exhibit excellent performance in terms of specific surface area, micropore volume, nitrogen and sulfur content, particularly showing outstanding CO2 adsorption and separation capabilities, surpassing most biomass-derived carbon materials.