Synthesis of KOH-activated porous carbon materials and study of hydrogen adsorption

The authors have studied the hydrogen storage capacity of activated carbon species synthesized under various conditions of KOH activation treatment. Rice husk and PAN (Poly-acrylonitrile) fiber precursor were used as the raw materials. The activated PAN fiber carbons have larger micropore volumes than the rice husk carbons. The synthesized materials show hydrogen storage capacities that are proportional to their micropore volumes. At the same time, hydrogen storage capacity is also affected by micropore size; smaller micropores are preferable for hydrogen storage. The micropore sizes around 0.9-1.3 nm is more suitable for hydrogen storage at ambient temperatures. The highest hydrogen adsorption capacity for a KOH-activated PAN fiber precursor is 1.1 mass% at 303 K/30 MPa, while that for a KOH-activated rice husk carbon is 1.0 mass% at 303 K/27 MPa.