Adsorption of hydrogen on activated carbons prepared by thermal activation : Hydrogen storage

Abstract

Microporous activated carbons were prepared from date pits using thermal activation with CO ₂ or steam. The adsorbents were characterized by N ₂ and CO ₂ adsorption at 77 K and 273K, respectively. The H ₂ adsorption was measured at 298K and 100 bar using a volumetric equipment. To increase the hydrogen storage, activated carbons are doped by metals. The results show that the H ₂ adsorption capacity is influenced by the size and volume of micropores in the activated carbon adsorbent. A relationship between hydrogen adsorption capacity calculated using Langmuir isotherm and the volume of narrow micropores deduced from the CO ₂ adsorption isotherm at 273 K was found. A correlation was also found between both micropore volumes and the amount of hydrogen adsorbed at 298 K and 100 bar. Additionally, vanadium doping of activated carbons could positively influence hydrogen adsorption.