Preparation of activated biomass carbon from pine sawdust for supercapacitor and CO2 capture

Biomass based carbon has captured more and more attention because it is environmentally friendly and has properties of low cost and ideal sustainability. In this study, three kinds of activated biomass carbons (ie, ABC-700, ABC-800 and ABC-900) were first carbonized through pine sawdust pyrolysis and then activated using KOH under three different activation temperatures (ie, 700 degrees C, 800 degrees C and 900 degrees C). The structure properties of the prepared activated biomass carbons were characterized by N-2-adsorption/desorption, SEM, TEM, XRD, Raman, XPS, TG and ultimate analysis. To clarify the activation mechanism, the gas products produced during KOH activation process were measured online with an ETG gas analyzer. The performance of the activated biomass carbons derived from pine sawdust for supercapacitor and CO2 capture was then evaluated. The predominant gas products during the activation process are H-2 and CO. It indicates that the porous structure was created by using an enhanced etching reaction between carbon atoms and KOH. An increment of the activation temperature from 700 to 900 degrees C results in the increase of surface area (from 1728.66 to 2330.89 m(2)/g) and total pore volume (from 0.671 to 1.914 cm(3)/g). Among the three samples, ABC-900 exhibits the maximal specific capacitance of 175.6 F center dot g(-1) and high energy density of 24.39 Wh center dot kg(-1) at the 0.5 A center dot g(-1). And the ABC-700 shows the maximal CO2 capture capacity of 4.21 mmol/g and high selectivity of CO2 over N-2 at 298 K and 1 bar. In addition, ABC-700 also has excellent stability and reproducibility after 15 times adsorption-desorption cycles. The unexceptionable electrochemical performance and adsorption capacity of the biomass-carbons show its broad application prospects in the field of supercapacitors and CO2 capture.