Preparation of activated carbon with high surface area for high-capacity methane storage

Activated carbon (AC) was fabricated from corncob, which is cheap and abundant. Experimental parameters such as particle size of corncob, KOH/char weight ratio, and activation temperature and time were optimized to generate AC, which shows high methane sorption capacity. AC has high specific surface area (3227 m2/g), with pore volume and pore size distribution equal to 1.829 cm3/g and ca. 1.7-2.2 nm, respectively. Under the condition of 2°C and less than 7.8 MPa, methane sorption in the presence of water (Rw = 1.4) was as high as 43.7 wt% methane per unit mass of dry AC. The result is significantly higher than those of coconut-derived AC (32 wt%) and ordered mesoporous carbon (41.2 wt%, Rw=4.07) under the same condition. The physical properties and amorphous chaotic structure of AC were characterized by N2 adsorption isotherms, XRD, SEM and HRTEM. Hence, the corncob-derived AC can be considered as a competitive methane-storage material for vehicles, which are run by natural gas.