Biomass derived nitrogen and sulfur co-doped porous carbons for efficient CO2 adsorption

In this work, novel nitrogen and sulfur co-doped porous carbons were synthesized by thiourea modification of carbonized hazelnut shell, then followed by KOH activation. In current preparation protocol, thiourea acted as both N and S agent, thereby, nitrogen and sulfur were simultaneously doped into the carbon skeleton by a single-step reaction. After KOH activation, the resultant sorbents hold advanced porosity and a certain amount of N and S contents. This series of sorbents possess the highest CO2 uptake of 4.30 and 6.44 mmol g−1 at 1 bar, 25 °C and 0 °C, respectively. Comprehensive investigations found that the joint effects of narrow microporostiy, N and S content govern the CO2 uptake of these adsorbents. Moreover, these adsorbents display various exceptional CO2 adsorption performances such as excellent reversibility, fast CO2 adsorption kinetics, moderate heat of adsorption, good CO2/N2 selectivity and high dynamic CO2 capture capacity. Therefore, these hazelnut shell derived N, S co-doped carbons are promising in actual CO2 capture.