Hydrogen Adsorption on Carbon Materials at High Pressures and Different Temperatures

In this work, we present experimental results corresponding to H₂ adsorption at high pressures and different temperatures (77 and 298 K) for a wide variety of carbons materials in order to analyze the effect of the porosity on the H₂ adsorption capacities in gravimetric basis. Likewise, we point out the importance of the packing density of the materials in order to obtain high H₂ adsorption capacities in volumetric basis and high total storage capacities. At 298 K, the H₂ adsorption capacity depends on both the total micropore volume and the micropore size distribution. At 77 K, H₂ adsorption depends only on the total micropore volume of the carbon material. Packing density of the carbon materials decreases with increasing the porosity development. Therefore, a good balance between porosity and packing density is needed. The total H₂ storage on the best activated carbon at 298 K and 20 MPa is 16.7 g H₂/L and 38.8 g H₂/L at 77 K and 4 MPa.

Keywords: active carbon; hydrogen adsorption; hydrogen storage; packing density