High hydrogen uptake capacity of mesoporous nitrogen-doped carbons activated using potassium hydroxide

Mesoporous nitrogen-doped carbons activated using potassium hydroxide have large surface areas and high pore volumes, are studied for their hydrogen storage properties. The activated material can store 6.84 wt.% of hydrogen at 77 K under a pressure of 20 bar, which is estimated to correspond to a maximum capacity of 8.24 wt.% based on the Langmuir simulation. The hydrogen adsorption values show linear relationships with the volumes of micropores and small mesopores under those conditions, which indicates that the small mesopores between the sizes 2 and 3 nm also make contributions to the hydrogen adsorption at high pressure.