The effects of hydrogen on KOH activation of petroleum coke

KOH activation of petroleum coke (PC) was conducted with 30 vol%H2 + 70 vol% N2 as carrier gas. TG-DTG, FTIR, elemental analysis, N2 adsorption, GC and XRD techniques were used to investigate the effects of hydrogen on the activation. During the initial stage of the activation, i.e. the carbonization of the PC, additional CH and CH2 species were formed due to the chemisorption of hydrogen on the nascent sites of the PC created by the removal of the surface heteroatom groups. The formation of the CH and CH2 species increased the quantity of ‘active sites’ which is favorable to the further activation reaction, and developed the porous structure of the activated carbons. The micropore volume and BET surface areas of the activated carbon prepared under 30 vol% H2 + 70 vol% N2 and with a relatively low KOH/PC weight ratio of 2:1 have been increased from 0.78 cm3/g and 1936 m2/g to 0.97 cm3/g and 2477 m2/g, respectively, compared to that prepared in pure N2 atmosphere with the same KOH/PC ratio.