Oxygen-rich precursors via glycerol organosolv treatment: Preparation of activated carbon from hazelnut shell and its structural components for possible use in electrodes for supercapacitors

Abstract

Bio-based activated carbon is a promising porous material for the use in electrodes for supercapacitors due to its low-cost production, high surface area with controllable pore structure and better thermal properties. Apart from activation type and conditions, the content of lignocellulosic biomass (namely cellulose, hemicellulose and lignin) is also a critical parameter on textural properties of activated carbon. In the present study, glycerol organosolv treatment was applied to fractionate lignin and cellulose from hazelnut shells. Hazelnut shell, lignin and cellulose-rich pulp mixed separately with KOH at a ratio of 1:2, and each mixture was activated for 1 h at 800 °C. FTIR results showed that lignin-based (AL) and cellulose-based activated carbons (AC) had more oxygen-containing functional groups, while AL had more aromatic structure. While activated carbon of hazelnut shell (ANS) had the highest specific surface area (1052.2 m2/g) and micropore volume (0.427cm3/g), AC had the least specific surface area (319.07 m2/g) and micropore volume (0.107cm3/g). While AL and ANS had microporous structure, AC was classified as mesoporous activated carbon. Due to high amount of oxygen-rich surface functional groups, high specific surface area and pore diameter of higher that 1 nm, activated carbon of hazelnut shell is a good candidate to be used as an electrode material. But, since the specific surface area and pore diameter are not the only factors that affect the capacitance, future work will include an electrochemical performance test to ANS, AL and AC.