Oak-tree-based white charcoals were subjected to high-temperature heat treatment at up to 2400 °C to analyze changes in

their surface morphology and internal structure using scanning electron microscopy and transmission electron microscopy.

When the treatment temperature was increased, micropores became smaller and disappeared, but macropores and mesopores

remained, resulting in an increase in average pore size. At treatment temperatures of 2000 °C or higher, all the pores disappeared

and the internal structure changed into a dense graphite-like structure. The X-ray diff raction patterns of charcoals

heat-treated at 1800 °C or higher in an argon atmosphere exhibited a sharp peak near 2 θ = 26.5°, and Raman spectroscopy

showed clear D and 2D bands near 1360 and 2680 cm −1 , respectively, indicating that carbon graphite crystals were developing.

At 2400 °C for 10 min., the interlayer distances ( d 002 and d 100 ), L c and L a of the graphite crystallites were 0.34, 0.21,

23.00, and 6.13 nm, respectively. The presence of the D band and the I G /( I G + I D ) ratio confi rmed that the newly developed

structure was turbostratic. The Brunauer–Emmett–Teller (BET) adsorption isotherm of the as-received charcoals exhibited

peculiar characteristics in which Types I and IV were mixed. This result is due to low-pressure hysteresis, in which nitrogen

is embedded in the crevices of charcoal during adsorption and is hardly desorbed during desorption. This low-pressure

hysteresis disappeared as increasing the temperature, the adsorption isotherm of charcoal treated at 2400 °C was Type II,

and the specifi c surface area was 8.45 m 2 /g, indicating that the charcoal was completely transformed to nonporous graphite.