Development of glycerol based carbon having enhanced surface area and capacitance obtained by KOH induced thermochemical activation

Abstract

The investigation describes surface modification of a glycerol-based carbon for enhanced capacitance. Glycerol was reacted with sulphuric acid, and the resulting carbon (GBC-120) was impregnated with known amount of KOH. The mixture was heated at 800 degrees C in N sub(2) atmosphere to obtain thermochemically activated carbon GBC sub(K). For comparison, GBC-120 was also heated in absence of KOH in N sub(2) atmosphere at 800 degrees C to prepare carbon GBC-800. The infrared spectra display bands at 1625 and 1073 cm sup(-1), respectively due to C double bond C and SO sub(3)H functionality. BET analysis revealed that thermochemical activation resulted in evolution of pores in carbon structure with relatively large pore volume of 1.76 cm sup(3) g sup(-1) and surface area of 1653 m sup(2) g sup(-1) for GBC sub(K) in comparison to very low pore volume (0.06 and 0.08 cm sup(3) g sup(?1)) and surface area (21 & 425 m sup(2) g sup(-1)) for samples GBC-120 and GBC-800 respectively. The activated carbon GBC sub(K) showed significantly higher specific capacitance of 219 mF cm sup(-2) as compared to commercial activated carbon and CNT.