H_2气氛下KOH活化石油焦制备活性炭及其电化学性质

Preparation of Activated Carbon From Petroleum Coke With KOH as Activation Agent in the Presence of H_2 and Its Electrochemical Performance

以石油焦为原料、氢氧化钾为活化剂,在H2存在下系统考察了碱/焦质量比、活化温度、活化时间以及在载气中H2含量对所得活性炭孔结构的影响,并将所制活性炭用于双层电极材料。结果表明,当碱/焦质量比为3、活化温度为780℃、活化时间为60min以及载气中的H2体积分数为30%时,制备出的活性炭比表面积和总孔容分别为2824m2/g和1.56cm3/g。与在相同的条件下,未引入H2时制得的活性炭相比,比表面积和孔容分别提高了约400m2/g和0.40cm3/g。当扫描速率分别为5mV/s及100mV/s,其质量比电容值分别为289F/g和180F/g,与未引入H2时制得的活性炭相比,分别提高了21%及114%。因此,在活化体系中引入H2,促进了活性炭孔隙结构的发展,从而使其表现出更优异的电化学性能。

Activated carbon （AC） was prepared from petroleum coke （PC） with KOH as activation agent in the presence of H2 and used as the materials of electric double-layer capacitor （EDLC）. The effects of different preparation variables, including KOH/coke mass ratio, activation temperature, activation time and content of H2 in the carrier gas on the porosity development of the AC were investigated. At the KOH/coke mass ratio of 3, activation temperature 780℃, activation time 60 min and carrier gas of 30%H2-}-70%N2 with a total flow rate 140 mL/min, the AC with specific surface area of 2824 m2/g and pore volume of 1.56 cmS/g was obtained. The BET surface area and pore volume of the AC prepared in the presence of 30%H2 increased by 400 m2/g and 0.40 cm3/g, respectively, compared with that of the AC prepared in the presence of pure N2. At the scanning rate of 5 mV/s and 100 mV/s, the gravimetric specific capacitance of the electric double layer capacitor made from the AC prepared under 30%H2＋70%N2were 289 F/g and 180 F/g, which increased by 21% and 114%, respectively, in comparison with that from the AC prepared in the N2 atmosphere. It was deduced that the presence of H2 in the activation system was favorable to the porosity development of AC, which endowed it a better electrochemical performance.