Given the dual threats of ‘peak oil’ and anthropomorphic climate change, suitable energy vector replacements for fossil fuels need to be sought quickly. Hydrogen has long been proposed as one solution, particularly for light duty vehicle applications, due to its abundance, relative ease of production and the emission of only water upon its full combustion, making it a ‘zero carbon’ fuel. Despite hydrogen’s very high gravimetric energy density, its very low mass density in its elemental form means it requires densification in order for enough hydrogen to be stored in a low volume to provide sufficient range for a vehicle. The current industrial standard for this is compressing the gas to 70 MPa. However, this method comes with an inherent safety risk and requires lightweight, mechanically strong and expensive materials to contain the pressure. One alternative method to this is the use of adsorption on microporous materials to densify hydrogen effectively at lower pressures. This study focuses on two such materials: the polymer of intrinsic microporosity PIM-1, and the metal organic framework (MOF) material MIL-101. PIM-1 is a highly interesting microporous material as it is a polymer whose chain molecules are both rigid and kinked, meaning that the chains do not relax fully into one another and therefore leave free volume in the material . The polymer is fully soluble in polar aprotic solvents, allowing for solvent casting into films that retain the microporosity, a manufacturing technique unavailable to many porous materials. However, PIM-1 is a limited adsorbent, with BET surface areas reported to be ~ 800 m2 g-1, and a hydrogen uptake of 1.45 wt% at 77 K and 10 bar . Therefore, we propose to enhance the adsorptive properties of PIM-1 by combination with MIL-101 in mixed matrix membrane-style films. MIL-101 is a popular and well characterised MOF, consistently showing BET surface areas ≥ 3000 m2 g-1 and hydrogen uptakes as high as 6 wt% at 8 MPa and 77 K . This work synthesises PIM-1 and MIL-101 separately, as well as a number of composites of the two materials. All these materials are then tested for their adsorptive (N2, CO2, H2 isotherms) and thermal (TGA, DSC) properties, and the results presented in ‘rule of mixtures’-style comparisons. Each of the high pressure hydrogen isotherms will also be modelled in preparation for a conceptual tank design based around these materials. References  P.M. Budd, E.S. Elabas, B.S. Ghanem, et al. Adv Mater., 16, 456–459. (2004)  N.B. McKeown, P.M. Budd & D. Book. Macromol. Rapid Commun. 28, 995–1002 (2007)  M. Latroche, S. Surblé, C. Serre, et al. Angew. Chem. Int. Ed 45, 8227–8231 (2006)
|Publication status||Unpublished - 2017|
|Event||11th International Symposium on the Characterization of Porous Solids (COPS-XI) - Palais des Papes, Avignon, France|
Duration: 14 May 2017 → 17 May 2017
|Conference||11th International Symposium on the Characterization of Porous Solids (COPS-XI)|
|Period||14/05/17 → 17/05/17|
Holyfield, L., Weatherby, N., Burrows, A., & Mays, T. (2017). Evaluation of PIM-1/MIL-101 Composites for Use in a Hybrid High Pressure Hydrogen Storage System. Poster session presented at 11th International Symposium on the Characterization of Porous Solids (COPS-XI) , Avignon, France.