STORAGE OF HYDROGEN ON CARBON MATERIALS: EXPERIMENTS AND ANALYSES |
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Authors: | Li Zhou Yan Sun Yaping Zhou |
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Affiliation: | 1. High Pressure Adsorption Laboratory (State Key Laboratory of Chemical Engineering) , School of Chemical Engineering and Technology, Tianjin University , Tianjin, China zhouli-tju@eyou.com;3. High Pressure Adsorption Laboratory (State Key Laboratory of Chemical Engineering) , School of Chemical Engineering and Technology, Tianjin University , Tianjin, China;4. Group of Physical Chemistry , School of Science, Tianjin University , Tianjin, China |
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Abstract: | Superactivated carbon and carbon nanotubes are both considered potential hydrogen carriers. Adsorption isotherms of H2 on activated carbon AX-21 and multi-wall carbon nanotubes were collected with a volumetric method for the temperature range of 77, 233–298 K and pressures up to 7 or 10 MPa. Based on the experimental data for 233–298 K, the limiting heats of adsorption of 7.6 and 1.8 kJ/mol were obtained for activated carbon and carbon nanotubes, respectively. The absolute adsorption was determined with a recently presented method, and the adsorption behavior of H2 on carbon nanotubes was thus reasonably explained. A comparison was given for the storage capacities of compression alone and of filling powder or pellets of the two materials. It was concluded that adsorption of H2 on carbon nanotubes is too weak to enhance storage, but activated carbon enhances storage capacity considerably. The weight percentage of hydrogen stored in carbon powder reaches 10.8% at 77 K and 6 MPa, including the quantity compressed in the void space, and 4.1 kg H2 was stored in a 100-liter container filled with carbon pellets for the same condition. |
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Keywords: | Hydrogen energy Storage Adsorption Activated carbon Carbon nanotubes |
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