Microstructure regulation of super activated carbon from biomass source corncob with enhanced hydrogen uptake

A series of super activated carbon have been prepared by potassium hydroxide activation of corncob. The as-obtained samples were characterized by SEM, TEM and N2-sorption. The results show morphologies and textural of activated carbon are highly depended on the activation temperature, heating rate, whereas the activation time is not a key factor. Morphologies and porous structure of activated carbons can be regulated by adjusting preparation parameters. A super activated carbon with BET surface area of 3530 m2/g and total pore volume of 1.94 cm3/g is obtained. However, the other activated carbon with smaller pore size exhibited the highest hydrogen uptake capacities exceeding 2.85 wt% at −196 °C and 1.0 bar, whose BET surface area is only 2988 m2/g. The correlation investigations show the micropore volume between 0.65 nm and 1.5 nm can be more important than BET surface area and total pore volume for hydrogen uptakes at −196 °C. The present results indicate that the corncob-derived activated carbons can be promising materials for hydrogen storage.