| AVS 55th International Symposium & Exhibition | |
| Energy Science and Technology Focus Topic | Monday Sessions |
| Session EN+SE+NS+SS-MoA |
| Session: | Hydrogen Storage |
| Presenter: | N. Nijem, University of Texas at Dallas |
| Authors: | N. Nijem, University of Texas at Dallas J.-F. Veyan, University of Texas at Dallas J. Li, Rutgers University Y.J. Chabal, University of Texas at Dallas |
| Correspondent: | Click to Email |
Hydrogen storage is one of the most challenging problems in hydrogen-based energy technology. One of the goals of hydrogen storage is the ability to store a high volumetric density of hydrogen at room temperature. As a result, studies exploring hydrogen interaction in storage materials are important to facilitate further development of materials. Metal-organic Frameworks are promising candidates for hydrogen storage because their high surface area and porosity facilitate high hydrogen physisorption on specific sites of the structures. This work explores the incorporation of hydrogen into the structure using infrared (IR) absorption spectroscopy. IR spectroscopy can distinguish possible H2 binding sites based on the perturbation of the internal H2 stretch mode. The measurements are performed at room temperature on three different types of MOF structures, two of which have the general formula [M(bdc)(ted)0.5]-2DMF-0.2H2O, differing in the metal core M (Ni and Zn). These two compounds are isostructural and crystallize in the tetragonal phase (space group P4/ncc), they construct a 3D porous structures with relatively large pore size (~7-8Å, pore volume (~0.63-0.84 cc/g) and BET surface area (~1500-1900 m2/g). Another type of MOF is the [Ni3(HCOO)6]-DMF structure which crystallizes in space group P21/c and features a 1D open channels with smaller pore diameters (~5-6 Å). Preliminary results show perturbation of the H2 gas vibrational modes leading to a ~30 cm-1 shift of the ortho- and para- peaks of the unperturbed H2. This perturbation is due to the interaction of the hydrogen with the MOF and can be seen as evidence of the hydrogen adsorbed onto specific sites of the MOF. Although the data are taken for high pressure H2 gas at room temperature, the shift is consistent with previous observation of Bordiga et al.1 performed at very low pressures and temperatures. The intensities of the perturbed ortho- and para- H2 peaks have a linear dependence with pressure, indicating that the perturbation of the H2 with the MOF lattice is dominant, i.e. H2-H2 interactions are much less important than in the pure H2 gas.
1 S. Bordiga, J. G. Vitillo, G. Ricchiardi, et al., Interaction of hydrogen with MOF-5 Journal of Physical Chemistry B 109, 18237 (2005).