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BASF Develops Method for Industrial-Scale MOF Synthesis; Trials Underway in Natural Gas Vehicle Tanks

Nanocubes made of metal organic frameworks (MOFs) could serve as a medium for gas storage. Photo: BASF. Click to enlarge.

BASF research scientists have developed a method for solvent-free industrial-scale manufacture of metal organic frameworks (MOFs)— highly crystalline structures with nanometer-sized pores that allow them to store hydrogen and other high-energy gases. MOFs produced by the new method are currently being trialed for natural gas storage in heavy duty vehicles.

The larger specific surface area and high porosity on the nanometer scale enable MOFs to hold relatively large amounts of gases. The pores are adjustable in terms of size and polarity and so can be fine-tuned for specific applications.

Used as storage materials in natural gas tanks, MOFs offer a docking area for gas molecules, which can be stored in higher densities as a result. (Earlier post.) The larger gas quantity in the tank increases the vehicle’s range.

An advantage of the production method developed by BASF is that it uses no organic solvents. The simple method gives a higher material yield from an aqueous medium and is suitable for existing BASF production plants, the company says.

MOFs were discovered toward the end of the 1990s by US chemist Omar M. Yaghi (then at University of Michigan, now UCLA). (Earlier post.) BASF researchers contacted him after reading his 1999 article in the journal Nature and have been collaborating with Professor Yaghi since then on the synthesis of metal-organic frameworks.

The aim is to develop MOFs with the largest possible surface area and storage density. Professor Yaghi recently succeeded in synthesizing MOF-210, a zinc carboxylate with a surface area of more than 10,000 square meters per gram of material. For comparison: the highest surface areas of previous MOFs averaged 5,000 square meters per gram. A paper on the development (Furukawa et al) was published in the 23 July issue of the journal Science.

Given the exceptional properties of such materials, it is expected that MOFs with ultrahigh surface area would exhibit exceptional gas storage capacity. Accordingly, this series of MOFs was subjected to high-pressure hydrogen (77 K) and methane (298 K) adsorption so as to examine their potential utility in the storage of gaseous fuels...The calculated gravimetric hydrogen density in MOF-210 (176 mg g–1) exceeds that of typical alternative fuels (methanol and ethanol) and hydrocarbons (pentane and hexane). MOF-200 and -205 also show large total hydrogen uptake (163 and 123 mg g–1, respectively); again, these values are higher than MOF-177.

Methane uptake was measured at 298 K and up to 80 bar; under the present experimental conditions, all isotherms were not saturated. Although the excess methane uptake in MOF-200, -205, and -210 (234, 258, and 264 mg g–1 at 80 bar, respectively) were smaller than that in PCN-14 (253 mg g–1 at 290 K and 35 bar, respectively), the calculated total uptakes (446, 394, and 476 mg g–1 for MOF-200, -205, and -210, respectively) were more than 50% greater than those of PCN-14. Moreover, the corresponding volumetric methane densities in the present MOFs are respectively 2, 3, and 2.5 times greater than volumetric bulk density (grams per liter) of methane at the same temperature and pressure. Because the isotherms are nearly linear up to 80 bar, these materials can deliver most of the sorbed methane in the pressure range between 10 to 200 bar.

...The ultrahigh surface areas exhibited by MOF-200 and -210 are near the ultimate limit for solid materials. To appreciate this, it is useful to note that all these compounds have a volume-specific surface area in the range of 1000 to 2000 m2 cm–3 = 1 x 109 to 2 x 109 m–1, and for a cube of edge d the external surface area/volume is 6d2/d3 = 6/d. Thus, for a monodisperse powder of cubic nanoparticles to have external surface that is equal to that of these MOFs the cube edge would have to be only 3 to 6 nm, which is a size far too small to practically realize in stable dry powders and therefore impossible to access the full surface area of such particles. This analysis emphasizes that MOFs are truly “nanomaterials” in the sense that they can be designed to give volume-specific surface areas that are equal to the external surface areas of nanometer-sized particles.

—Furukawa et al.


  • Hiroyasu Furukawa, Nakeun Ko, Yong Bok Go, Naoki Aratani, Sang Beom Choi, Eunwoo Choi, A. Özgür Yazaydin, Randall Q. Snurr, Michael O’Keeffe, Jaheon Kim, Omar M. Yaghi (2010) Ultrahigh Porosity in Metal-Organic Frameworks. Science Vol. 329. no. 5990, pp. 424 - 428 doi: 10.1126/science.1192160


Nick Lyons


Moreover, the corresponding volumetric methane densities in the present MOFs are respectively 2, 3, and 2.5 times greater than volumetric bulk density (grams per liter) of methane at the same temperature and pressure.

Extrapolating, this seems to imply that a Civic GX could have a range of 600 miles instead of the current ~200 miles using the same sized storage tank. Or have a smaller CH4 tank and leave room for a gasoline tank as well for dual-fuel capability.


This puts methane on par with methanol densities which sounds good until you consider heavy tanks with the adsorbent weight and strong enough to take the pressure. Then you still have to purify and compress the natural gas. It is a nice development and we will see how it goes. For trucks serving ports to warehouses, there may be an application.


Good also for the Clarity FCX. Storage is only one of the impediments to FCVs. Production of H2 is another. Eventually we may learn the way to crack the strong bond in water.


The Clarity is a good example. Hydrogen from their home refueling station is already pure and compressed, now they get more range with the same sized tanks. They will weigh more, but that is not a big deal.


Err SJC, are you taking both sides now? RE; "sounds good until you consider heavy tanks" and "They will weigh more, but that is not a big deal."

Are you for or against or what?


Heavy vehicles (trucks, buses, tractors, locomotives etc) could easily take an extra tonne for H tanks to get enough range (500+ miles or about 8 hours) between fuel stops.

Compressed Hydrogen could be made locally (at the major fuel stop points) by different means. Eventually, cracking water may be doable at an affordable price.


I was comparing adsorbed natural gas to methanol, then I was talking about an improved Clarity. Those are two different applications which shows it may not be so good for one and better for another. There is no contradiction.


H2 production isnt a problem for heavy trucks nor is storage. They already have 50 kg comercial storage tanks for h2. Thats enough for 1000 kwh of energy storage. And h2 costs less per mile then diesel does.

We just have to wait the last few years for fuel cells to go into mass production and drop radicaly in cost and blamo its a done deal.


An improved Clarity means greater range, smaller tank and/or lower pressure. If you are really into H2 cars, this is a plus. Now you do not have to have a tank at 10,000 psi to go 240 miles.

In the case of an NG car, saying you are getting near the energy density of methanol just begs comparison. The methanol car has a lighter tank not under pressure, NG car has a much heavier tank that is under pressure for equivalent range.


The clarity only used a 5kpsi tank as it uses an absorbative thingy in its tank its the gm whatzit that uses 10kpsi as its still just using a carbon fiber tank.


Do BASF invest in such stuff on their own. Why? What is the point? Why hydrogen? Why not DME which is becoming reality in Sweden and could be produced from any stuff and liquidized at 5 bar? Methane or LNG could be solution for USA market but on limited scale and finally repeating oil pattern. For European market that is not solution at all.


You are right, the Clarity tank is 5000 psi, but I find no mention of an absorbent. You can see that it is a rather large tank in this picture.


If you don't need the pressurised tanks, you can build them into a much easier shape to package.

There is also the option for using natural gas in a diesel engine using diesel as the ignition source, you can substitute up to 90 / 95% of the diesel with natural gas under load.


The large heavy tanks are under pressure and provide minimal range, this and other reasons are why both natural gas and hydrogen are questionable. The Honda Civic GX natural gas car had just over 100 mile range, with this it could go further with the same tank, but still under considerable pressure. The tank and absorbent would weigh quite a bit more than just the tank alone.

A 300 pound tank might carry less than 10 pounds of H2. A 50 pound tank could carry more than 100 pounds of methanol. From a practical standpoint, liquid fuels offer advantages. More range, less weight, at a lower cost with no high pressure. It is also easy to retrofit existing gasoline stations to dispense M85.


Yes the honda clarity uses an absorbative material in its tank and the tank isnt all that big either its certainly alot smaller then the gm tanks;/

Still I wouldnt be chocked if this new material manages to squeeze the size down a good bit.


I have seen no mention of any absorber in the tanks, if you have a link please post it. The picture link I posted shows the size of the tank with a hydraulic lift and two people installing it. It sure looks a lot bigger and heavier than a standard gasoline tank.

At 5000 psi it would have to be inspected periodically. 3000 psi air tanks have a service life and after that they can not be refilled.



I scanned and searched the link and found no mention of the latest Honda Clarity using an adsorbent in their H2 tank. They will probably use one at some point in the future.


The last version of the clarity as it says was to use the absorbant tank. That aerticle is old tho so it cant say for sure that it did..

SEPT the honda clarity final version in fact only has 1 5kpsi tank that is far far far too small to be anything other then an absorbant filled tank as it can hold 4.1 kg of h2.

Oh and I should warn you your clarity tank image is from an older model that used 2 5kpsi tanks and we dont know if the tanks it used are the same size as the one tank the newest model uses.


Well it seems like Honda would like a smaller tank and more range. The whole adsorbent effort here in the U.S. is a government goals program. They have set goals for adsorbent performance targets and that is what companies are shooting for.

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