Effects of thermal activation conditions on the microstructure regulation of corncob-derived activated carbon for hydrogen storage

Activated carbons derived from corncob (CACs) were prepared by pyrolysis carbonization and KOH activation. Through modifying activation conditions, samples with large pore volume and ultrahigh BET specific surface area could be obtained. The sample achieved the highest hydrogen uptake capacity of 5.80 wt% at 40 bar and −196 °C. The as-obtained samples were characterized by N2-sorption, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Besides, thermogravimetric analysis was also employed to investigate the activation behavior of CACs. Detailed investigation on the activation parameters reveals that moderate activation temperature and heating rate are favorable for preparing CACs with high surface area, large pore volume and optimal pore size distribution. Meanwhile, the micropore volume between 0.65 nm and 0.85 nm along with BET surface area and total pore volume has great effects on hydrogen uptake capacities. The present results indicate that CACs are the most promising materials for hydrogen storage application.

Graphical AbstractThe effects of various thermal activation conditions on corncob-derived AC were investigated. As shown in the graphical abstract, higher activation temperature and moderate heating rate were favorable to the fabrication of AC for hydrogen storage.Figure optionsDownload full-size imageDownload as PowerPoint slide