Effect of potassium agents at activated carbon fabricated from rice husks on pore structure and hydrogen storage property

Abstract

Activated carbons were fabricated from carbonized rice husks (CRH) by the alkaline activation with KOH and K₂CO₃. The pore structure and stored hydrogen contents of activated carbons were investigated. The specific surface area of K₂CO₃ and KOH activated samples were 1177, 1247 m²/g, respectively. The meso-pore volume of K₂CO₃ activated sample was larger than KOH activated. On the other hands, the micro-pore volume of KOH activated sample was larger than K₂CO₃ activated. These results indicated that meso-pore was preferentially developed by K₂CO₃ activation and micro-pore was preferentially developed by KOH activation. The maximum storage hydrogen contents of activated carbon by KOH and K₂CO₃ were 0.57 and 0.43 wt %, at 298 K and about 10 MPa, respectively. Thus, it suggests that micro-pore influence on stored hydrogen contents is greater than meso-pore. Consequently, for the fabrication of activated carbon which is utilized for hydrogen storage, KOH is an effective activation agent more than K₂CO₃.