Preparation and characterization of activated carbon fibers from liquefied wood by KOH activation

Activated carbon fibers (ACFs) have been prepared from liquefied wood (W-liq) by chemical activation with KOH, with a particular focus on the effect of KOH/fiber ratio in term of porous texture and surface chemistry. ACFs based on steam activation served as a blank for comparison. The properties of the ACFs were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen adsorption/desorption, Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The results show that the KOH-activated ACFs have rougher surfaces and more amorphous structure compared with the blank. The pore development was significant when the KOH/fiber ratio reached 3, and achieved a maximum Brunauer-Emmett-Teller (BET) surface area of 1371 m(2) g(-1) and total pore volume (V-tot) of 0.777 cm(3) g(-1), of which 45.3% belong to mesopores with diameters of 2-4 nm, while the blank activated at the same temperature had a BET surface of 1250 m(2) g(-1) and V-tot of 0.644 cm(3) g(-1), which are mainly micropores. The surface functional groups are closely associated with the KOH/fiber ratios. KOH-activated ACFs with KOH/fiber ratio of 3 have more oxygenated surface functional groups (C-O, C = O, -COOH) than the blank.