The effect of oxidation on the physical activation of pitch: Crystal structure of carbonized pitch and textural properties of activated carbon after pitch oxidation

The effect of oxidation on carbonization and physical activation of pitch was determined for synthesis of activated carbon (AC). The prepared AC from non-oxidized pitch exhibited a low specific surface area of 0.2 m2/g. On the other hand, the specific surface area of prepared AC from the oxidized pitch increased up to 729.6 m2/g even by same activation process. The introduced oxygen functional groups were almost removed during carbonization (with only 3.1% or less oxygen remaining); therefore, they did not directly affect the activation process. However, introduced oxygen functional groups prevented the rearrangement of the pitch molecules during carbonization. This effect decreased the crystallinity of the carbonized pitch and increased the number of defects present. The defects acted as active sites and improved the pore structure; thus, AC with a high specific surface area was prepared.