Influence of activation temperature on surface structure changes and adsorption properties of PAN-based carbon fibers

In this work, a series of activated carbon fibers have been prepared by CO₂ activation of oxidized PAN-based carbon fibers at 700, 800, 900 and 1000 °C for 2 hrs, respectively. The adsorption properties of the activated carbon fibers (ACFs) were studied as a function of the heat treatment temperature (HTT). The ACFs were characterized by N₂ gas adsorption and pH value and acid-base values of the carbon surfaces. As a result, ACFs showed different BET surface areas, total pore volumes and pore size distributions, depending on activation conditions. Among them, the condition derived from temperature at 1000 °C for 2 hrs gave the highest BET surface area, total pore volume. When the activation temperature was less than 800 °C, the surface of ACFs have been developed in acidic nature, but basic properties have increased in increasing the HTT at higher than 900 °C.