Nitrogen-Doped Porous Carbons from Lotus Leaf for CO2 Capture and Supercapacitor Electrodes

In this work, N-doped porous carbons were synthesized by a one-step sodium amide activation of carbonized lotus leaf at 450-500 degrees C. The CO2 adsorption properties of the as-synthesized carbonaceous materials were carefully investigated. In addition, the supercapacitor performance of the optimized sample was also preliminarily explored to examine its potential as the electrode material. These lotus leaf-derived carbons possess good CO2 adsorption capacity up to 3.50 and 5.18 mmol/g at 25 and 0 degrees C under atmospheric pressure, respectively. It was found that the synthetic effects of narrow microporosity, N content, pore size, and pore size distribution of the sorbents decide their CO2 adsorption abilities under the ambient conditions. These lotus leaf-based carbons also demonstrate many excellent CO2 adsorption properties, such as good selectivity of CO2 over N-2, quick adsorption kinetics, moderate heat of adsorption, excellent recyclability, and high dynamic adsorption capacity. In addition, preliminary electrochemical studies show that the optimized sample has high capacitance (266 F/g) and excellent stability in cycling tests. These results indicate these lotus leaf-derived N-doped porous carbons have good potential in the application of CO2 capture and supercapacitor.