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Pure platinum alternative promises breakthrough in fuel cell technology

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May 25, 2010

The multi-metallic nanoparticle created for fuel-cell reactions uses a palladium core and ...

The multi-metallic nanoparticle created for fuel-cell reactions uses a palladium core and an iron-platinum shell (Image: Vismadeb Mazumder & Shouheng Sun, Brown University)

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The most obvious obstacles for the widespread adoption of fuel cell technology are cost and performance. Although they promise benefits over internal combustion engines and batteries in terms of environmental impact, they are still fairly limited in use for these reasons. One of the most expensive elements used in most fuel cells is platinum, but now researchers have created a unique core and shell nanoparticle that uses far less platinum, yet performs more efficiently and lasts longer than commercially available pure-platinum catalysts at the cathode end of fuel cell reactions.

The oxygen reduction reaction that takes place at the fuel cell’s cathode creates water as its only waste and it is there that up to 40 percent of a fuel cell’s efficiency is lost. Platinum has been the catalyst of choice for this reaction for many researchers, but it is expensive, and the reaction causes it to break down over time. The core-shell nanoparticle developed by researchers at Brown University and Oak Ridge National Laboratory addresses both of these problems.

The team created a five-nanometer palladium (Pd) core and encircled it with a shell consisting of iron and platinum (FePt). The trick was in molding a shell that would retain its shape and require the smallest amount of platinum to pull off an efficient reaction. The team created the iron-platinum shell by decomposing iron pentacarbonyl and reducing platinum acetylacetonate to result in a shell that uses only 30 percent platinum. Although the researchers say they expect to be able to make thinner shells and use even less platinum.

The researchers demonstrated for the first time that they could consistently produce the unique core-shell structures. In laboratory tests, the palladium/iron-platinum nanoparticles generated 12 times more current than commercially available pure-platinum catalysts at the same catalyst weight. The output also remained consistent over 10,000 cycles, at least ten times longer than commercially available platinum models that begin to deteriorate after 1,000 cycles.

The team created iron-platinum shells that varied in width from one to three nanometers. In lab tests, the group found the one-nanometer shells performed best.

“This is a very good demonstration that catalysts with a core and a shell can be made readily in half-gram quantities in the lab, they’re active, and they last,” said Brown graduate student, Vismadeb Mazumder. “The next step is to scale them up for commercial use, and we are confident we’ll be able to do that.”

Mazumder and Shouheng Sun, professor of chemistry at Brown, are studying why the palladium core increases the catalytic abilities of iron platinum, although they think it has something to do with the transfer of electrons between the core and shell metals. To that end, they are trying to use a chemically more active metal than palladium as the core to confirm the transfer of electrons in the core-shell arrangement and its importance to the catalyst’s function.

The study detailing the researcher’s findings is published in the Journal of the American Chemical Society.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag.   All articles by Darren Quick
7 Comments

I thought that the most obvious problem to the widespread adoption of hydrogen as an alternate fuel source was that it was a stupid idea...

Why would you use a fuel which is only 25% efficient to generate from electricity, has to be stored in a nickel lined ultra high pressure cylinder otherwise it will bleed out and if said ultra high pressure nickel lined vessel were ever punctured the resulatant blast would probably make current LPG bleves look like a nice holiday location...

I mean asside from that, the storage and distribution issues and the fact that its both mass and volume inefficient even when compared to a large stack of batteries it seems like a wonderful fuel.

Drew__1
26th May, 2010 @ 12:41 am PDT

there is also nickel hydrid fuel tanks, which does not store hydrogen in pressurized tanks.

search it on google.

bio-power jeff
26th May, 2010 @ 03:39 am PDT

Ever priced a NiMH tank Jeff?

Or priced H2?

One thing I want to know is what is a cycle in a fool cell? I'd just turn one on and run it. Give me life in hrs so it can be compared.

Lithium batteries are both far less expensive and 98% eff vs 25% or so for foolcells.

jerryd
26th May, 2010 @ 02:00 pm PDT

The first electric cars (1894 - 1900) had a range of 20 to 40 miles, still better than the 15 mile "range" of a horse. The average second generation EV (1901 - 1910) already boasted a mileage of 50 to 80 miles. The third generation of early electric cars (1911-1920), including larger vehicles that could seat 5 people comfortably, could travel 75 to more than 100 miles on a single charge - and this is still the range of electric cars today.

The current generation of Lithium Ion batteries weigh about 18.7 per KWh. A hydrogen fuel cell and tanks weigh about 4.4 lbs per KWh. The weight of the batteries is why the typical EVs have such short range (less than 100 miles)! By way of comparison the fuel Chevy Equinox is expected to enter the market with a greater than 300 mile range. The sooner that the EV guys understand that hydrogen is simply a more weight efficient battery that release electricity on demand, the sooner we will all stop using fossil fuels.

Lawrence Weisdorn
26th May, 2010 @ 03:03 pm PDT

thanks Bio Boy! I am surprised people don't know this old reliable alternative. Of course nickle is not light. But at least in a Hydrogen storage device, it serves a longer life than in a NiCd battery ...You have to look at the 1000 cycles before it "begins to deteriorate."Then you must compare the tank volume and the "fill er up" conveniences of compared to high or low tech battery packs and to fuel oil tanks too. How much trunk space does 200 miles take up? That 12 times the usual current sounds like get-up-and-go, to me!!! I'll be interested to see the scale specs for say a 1KwHour motor or a 5..

waltinseattle
26th May, 2010 @ 03:15 pm PDT

Nickel hydride or other "metal sponge" technology. The hydrogen is adsorbed (not aBsorbed), it sticks to the surface of the sponge metal.

The problem with such forms of hydrogen storage is the tank has to be heated to a high temperature to get the hydrogen out.

Why there's been so much research into this is this method of storage can't explode. Even if the tank is ruptured and there's a fire, it'll just burn as the fire's heat releases the hydrogen.

Other than needing high heat to release the hydrogen, the other problem is storage density. This system can't store anywhere near as much hydrogen as a regular pressure tank.

Facebook User
26th May, 2010 @ 03:23 pm PDT

Advancement in Fuel Cell technology.

Dr.A.Jagadeesh Nellore(AP),India

Anumakonda Jagadeesh
11th June, 2010 @ 04:32 pm PDT
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