H 2 气氛下KOH活化石油焦制备活性炭及其电化学性质研究

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 60min and carrier gas of 30%H2 +70% N2 with a total flow rate 140mL/min,the AC with specific surface area of 2824m2/g and pore volume of 1.56cm3/g was obtained.The BET surface area and pore volume of the AC prepared in the presence of 30% H2 increased by 400m2/g and 0.40cm3/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%N2 were 289F/g and 180F/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.