(731b) Hydrogen Adsorption On Ordered Mesoporous Carbons At Pressures Up to 1500 Bar

Hydrogen adsorption isotherms on four ordered mesoporous carbon (OMC) samples were measured volumetrically at 81, 273 and 298 K and hydrogen pressures up to 1500 bar. The OMC samples were synthesized with both soft-template and hybrid soft-hard template methods and characterized for their pore textural properties (BET, pore size distribution and pore volume), topology with TEM, and other physical and chemical properties. The four porous carbon samples have quite different pore textural properties (BET specific surface area varying from 570 to 1912 m²/g). Hydrogen adsorption and desorption isotherms were measured on 1 g of sample by a volumetric method on a Sieverts type experimental unit specifically designed for studies of solid gas reactions under gas pressures up to 2000 bar. A metal hydride storage system was used as a source of high-purity hydrogen (99.9999%) for this work. An equation of state suitable for highly compressed hydrogen was employed for calculating the adsorption amounts. To evaluate the excess adsorption capacity of the carbon adsorbents the adsorption system was calibrated with helium prior to the hydrogen adsorption measurements. The hydrogen adsorption and desorption isotherms on different OMC adsorbents will be compared and discussed. An excess adsorption amount as high as 4.2 wt.% was observed on an OMC sample with BET of 1912 m²/g at 81 K and 30 bar. The effects of pore textural properties (BET, pore size and pore volume) on hydrogen adsorption will be discussed in detail.