Synthesis of nitrogen and sulfur co-doped carbons with chemical blowing method for CO2 adsorption

Abstract

Heteroatom doped carbons have attracted great attentions as CO2 adsorbents. Herein, we presented a novel and facile strategy for the synthesis of nitrogen and sulfur co-doped carbons (NSCDCs) with chemical blowing method. Chitosan was used as the carbon and nitrogen source, and hydroquinonesulfonic acid potassium salt (HAPS) was used as the sulfur source and blowing agent. NSCDC with hierarchically porous structure was obtained after one-step carbonization of chitosan and HAPS mixture. The carbon exhibited surface area up to 1645 m2/g. HAPS promoted the formation of mesopores and macropores in the carbon. The nitrogen and sulfur contents were 2.54–2.62 and 1.63–6.70 at.%, respectively. NSCDC was also successfully synthesized by replacing chitosan with glucosamine hydrochloride derived hydrochar. The CO2 adsorption performances of NSCDCs were studied with pressure up to 20 bar. At 25 °C, the best CO2 uptakes at 1 bar and 20 bar were 2.4 and 12.9 mmol/g, respectively. At 1 bar, the carbon’s microporous structure was the most important factor; at 20 bar, the uptake was mainly decided by the total surface area and the pore volume of the carbon.