Effect of pre-carbonization of petroleum cokes on chemical activation process with KOH Original Research Article

The influence of pre-carbonization of petroleum cokes on the properties of the activated carbon precursors and final carbons activated with KOH was investigated by using TG–DTG, FTIR, XRD, and BET techniques. TG–DTG study revealed the decomposition of volatile species and FTIR analysis identified the presence of C–O, C–O–C, C–O–H and some alkyl species on the surface of the precursors. XRD results indicated that a disorder occurred after the carbonization at 500 °C and an order happened gradually with increasing the temperature. The decreases in the BET surface area and N2 adsorption capacity coincided with the reduction of the functional species on the precursor surface with the increase of the pre-carbonization temperature. These surface functional species were proposed to play a key role in the porosity development during the KOH activation. First, they reacted with KOH to form the intermediate C–O–K species, then the resultants further reacted with the carbon of the precursor, and finally developed the porous structure. As a result, the surface area and the pore size distribution of the activated carbon can be controlled by optimizing the conditions of the pre-carbonization and activation processes.