Hierarchical porous graphene oxide/carbon foam nanocomposites derived from larch for enhanced CO2 capture and energy storage performance

Abstract

The development of biomass-based carbon foams with hierarchical pore structures could lead to practical applications in CO2 capture systems and supercapacitors. However, these materials typically exhibit inferior adsorption and electrochemical characteristics because their pore structures are damaged during processing. The present work synthesized hierarchical porous graphene oxide (GO)/biomass-based carbon foam (GCF) nanocomposites from liquefied larch sawdust using in situ polymerization, foaming and carbonization steps. The GO enhanced the thermal stability of the foam while preventing collapse of the pore structure. The resulting GCF nanocomposites possessed hierarchical pore structures with greater ultramicroporosity than the original CF, especially with regard to the number of pores with sizes from 0.50 to 0.80 nm. Micropores with diameters less than 0.60 and 0.80 nm were found to be the primary factors determining CO2 adsorption at 0.15 and 1 bar, respectively, such that the GCF-0.2 (the addition of 0.2 wt%) exhibited the highest CO2 capacity of 4.99 mmol g−1 at 0 °C and 1 bar. These materials also showed CO2/N2 selectivity values up to 100.21, moderate heats of adsorption between 10.27 and 18.77 kJ mol−1 and good stabilities. The GCF-0.2 displayed a specific capacitance of 173.20 F g−1 at a current density of 1A g−1 in a 6 M KOH electrolyte and demostrated superior capacitance retention that could lead to applications in supercapacitors.