|The top-performing MOFs for hydrogen storage: MOF-177 and IRMOF-20|
Chemists at UCLA and the University of Michigan have achieved hydrogen storage concentrations of up to 7.5 wt% in Metal Organic Framework (MOF) material—exceeding the the DOE target of 6.5% by 2010 for application in hydrogen fuel-cell cars. (Earlier post.)
The storage was achieved at a low temperature of 77 Kelvin (-196º C or -321º F).
The researchers worked with a series of microporous MOFs under saturation pressures varying between 25 and 80 bar across the series. MOF-177 showed the highest uptake on a gravimetric basis (7.5 wt %) and IRMOF-20 showed the highest uptake on a volumetric basis at 34 g/L.
We have a class of materials in which we can change the components nearly at will. There is no other class of materials where one can do that. The exciting discovery we are reporting is that, using a new material, we have identified a clear path for how to get above seven percent of the material’s weight in hydrogen.
We have achieved 7.5 percent hydrogen; we want to achieve this percent at ambient temperatures.—Omar Yaghi, UCLA professor of chemistry
MOFs can be made from low-cost ingredients, such as zinc oxide and terephthalate, which is found in plastic soda bottles.
In previous research, Yaghi and colleagues reported that MOFs also can store large amounts of methane. Additionally, Yaghi has shown that MOFs store prodigious amounts of carbon dioxide at ambient conditions, a development relevant to preventing carbon dioxide emissions from power plants and automobile tailpipes from reaching the atmosphere.
We have materials that exceed the DOE requirements for methane, and we think we can apply the same sort of strategy for hydrogen storage.—Omar Yaghi
“Exceptional H2 Saturation Uptake in Microporous Metal-Organic Frameworks”; Antek G. Wong-Foy, Adam J. Matzger, and Omar M. Yaghi; J. Am. Chem. Soc., ASAP Article 10.1021/ja058213h S0002-7863(05)08213-2