Analysis of the hydrogen adsorption behavior on the typical adsorbing materials

For comparing the effects of the structural properties of adsorbents on the capability for hydrogen storage, three kinds of adsorbents, including activated carbon, graphene sheets (GF) and metal-organic frameworks (MOFs), were synthesized and undertaken adsorption equilibrium tests of hydrogen at temperature of liquid nitrogen. The structural characterization of the prepared samples were firstly conducted employing Micromeritics 3Flex for the adsorption data of nitrogen at 77 K. Then, the adsorption equilibrium tests of hydrogen on those adsorbents had been respectively measured under low pressure of 0-0.1 MPa at temperature of 77-87 K and under high pressure of 0.1-8 MPa at 77 K. Lastly, the relationships of the hydrogen uptake and the structural properties of the adsorbents were analyzed. Results show that the hydrogen uptake of the physical absorbents is mainly affected by the micro-pores with pore size less than 1nm under low pressure, but under high pressure, the maximum amount of excess hydrogen adsorption on the porous material is positively correlated with the BET specific surface area of the material, and the slope is 0.0059 mmol/m².