Hydrothermal synthesis of nitrogen-doped ordered mesoporous carbon via lysine-assisted self-assembly for efficient CO2 capture

摘要

Nitrogen-doped ordered mesoporous carbons (NOMCs) were synthesized by single-step hydrothermal self-assembly using F127 as a soft template, hexamine as a formaldehyde source, l-lysine as a polymerization catalyst, and 3-aminophenol as both carbon and nitrogen sources. The microstructure of the NOMCs was characterized by XRD, N-2 adsorption/desorption, TEM, FTIR, and XPS. The results indicated that the obtained NOMCs exhibited a large specific surface area, uniform pore size distribution and highly ordered 2-D hexagonal mesostructure (P6mm). Besides, the nitrogen was uniformly doped into the carbon framework in the form of various nitrogen species. The adsorption isotherms of CO2 and N-2 were also determined and could be well fitted by a DSL model. The capture capacity of CO2 was affected by both the nitrogen content and mesostructure of the adsorbents. Overall, NOMC-L-0.5 displayed excellent CO2 capture capacity (0 degrees C, 3.32 mmol g(-1); 25 degrees C, 2.50 mmol g(-1)), and still demonstrated great regenerability with only 2% loss after several CO2 adsorption/desorption cycles. Moreover, the CO2/N-2 selectivity calculated by IAST was as high as 43.2 at 25 degrees C in a typical composition of flue gas (binary mixtures with 15% CO2). The superior adsorption performance enables NOMCs to be a promising CO2 adsorbent in practical applications.