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

Abstract

• N, S co-doped porous carbons were synthesized from biomass hazelnut shell. • Thiourea acts both N and S agent. • The resultant carbon exhibits high CO 2 uptake, 6.44 mmol/g at 0 °C and 1 bar. • The sorbents also exhibit various other good CO 2 adsorption properties. • Joints effects of narrow microporosity, N and S content decides CO 2 uptake. 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 CO 2 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 CO 2 uptake of these adsorbents. Moreover, these adsorbents display various exceptional CO 2 adsorption performances such as excellent reversibility, fast CO 2 adsorption kinetics, moderate heat of adsorption, good CO 2 /N 2 selectivity and high dynamic CO 2 capture capacity. Therefore, these hazelnut shell derived N, S co-doped carbons are promising in actual CO 2 capture.