Biomass based N-doped porous carbons as efficient CO2 adsorbents and high-performance supercapacitor electrodes

Abstract In this report, a series of N-doped porous carbons were achieved using biomass lotus stalks as the precursor. A two-step synthesis method was employed to prepare carbonaceous adsorbents with different porous structure and surface chemical features. The as-obtained sorbents were characterized by multiple techniques and their CO2 adsorption properties were also comprehensively investigated. At 1 bar, these carbons demonstrate excellent CO2 uptake of 4.25 mmol g−1 at 25 °C and 6.59 mmol g−1 at 0 °C, respectively. The joint effect of narrow microporosity and doped N content was found to govern the CO2 adsorption capacity of these sorbents under 25 °C and 1 bar. Moreover, these biomass-derived carbons also display various other exceptional CO2 capture properties such as high CO2/N2 selectivity, excellent recyclability, suitable heat of adsorption, fast adsorption kinetics, and good dynamic adsorption capacity. The electrochemical study shows that this N-doped porous carbon based electrode possesses substantial specific capacitance (325F/g) and outstanding stability (retain rate of 95% after 5000 cycles). Therefore, these lotus stalk-based N-doped porous carbons have application possibility in CO2 capture and supercapacitor.