Porous Carbons Derived from Sustainable Biomass via a Facile One-Step Synthesis Strategy as Efficient CO2 Adsorbents

In this work, porous carbons were achieved from sustainable biomass lotus stalk. Unlike the common carbonization-activation two-step method, a facile one-step KOH activation procedure was explored to make the carbonaceous sorbents. The as-made adsorbents have advanced porous structures and hold superior CO 2 uptake, up to 3.68 and 5.11 mmol/g at 1 bar, 25 and 0 °C, respectively. After carefully checking the relationship of CO 2 uptake with each porous characteristic, the volume of narrow micropores is found to be the leading factor that determines the CO 2 adsorption abilities of the adsorbents under ambient conditions. Moreover, the narrower pore size distribution is also preferential to the adsorption of CO 2 . Apart from the high CO 2 uptake, these lotus stalk-derived adsorbents also possess extra excellent CO 2 capture properties such as good recyclability, fast adsorption kinetics, reasonable CO 2 /N 2 selectivity, suitable heat of adsorption, and high dynamic adsorption capacity. These results demonstrate that these cost-effective carbonaceous adsorbents developed by the facile one-step method have potential in the application of actual CO 2 capture.