Lignin-derived heteroatom-doped porous carbons for supercapacitor and CO2 capture applications

The present study reports the economic and sustainable syntheses of functional porous carbons for supercapacitor and CO2 capture applications. Lignin, a byproduct of pulp and paper industry, was successfully converted into a series of heteroatom-doped porous carbons (LHPCs) through a hydrothermal carbonization followed by a chemical activating treatment. The prepared carbons include in the range of 2.5 to 5.6wt% nitrogen and 54wt% oxygen in its structure. All the prepared carbons exhibit micro- and mesoporous structures with a high surface area in the range of 1788 to 2957m(2)g(-1). As-prepared LHPCs as an active electrode material and CO2 adsorbents were investigated for supercapacitor and CO2 capture applications. Lignin-derived heteroatom-doped porous carbon 850 shows an outstanding gravimetric specific capacitance of 372Fg(-1) and excellent cyclic stability over 30,000cycles in 1M KOH. Lignin-derived heteroatom-doped porous carbon 700 displays a remarkable CO2 capture capacity of up to 4.8mmolg(-1) (1bar and 298K). This study illustrates the effective transformation of a sustainable waste product into a highly functional carbon material for energy storage and CO2 separation applications.