Highly efficient nanoparticles could bring down the cost of fuel cells

July 22, 2014
Scientists at SLAC National Accelerator Laboratory and Technical University of Denmark have developed a new fuel cell catalyst that uses much less pricey platinum and is five times more active than platinum alone. If developed commercially, the new catalyst could bring down the cost of fuel cells for vehicles. Credit: iStockphoto.com/gchutka

(Phys.org) —Fuel cells are a promising, non-polluting way to power cars, but their platinum catalysts are so expensive that there's no way current technology could be economically scaled up for widespread use. Now scientists at the Department of Energy's SLAC National Accelerator Laboratory and the Technical University of Denmark have developed an alternative that would use just one-fifth as much of the pricey metal.

The new catalyst is a mixture of platinum and a second, cheaper element, yttrium, formed into whose size can be precisely controlled. Electron microscopy and X-ray studies show that yttrium atoms leach out of the surface of these particles, leaving a thin, dense, sturdy crust of platinum atoms to enthusiastically promote a key reaction in the fuel cell that converts into water.

The results were published July 13 in Nature Chemistry.

"We now have proof of principle that these nanoparticles work the way we had predicted," said report co-author Daniel Friebel, an associate staff scientist at SUNCAT Center for Interface Science and Catalysis, which is jointly run by SLAC and Stanford University. "The next step is to find a more efficient way to make these nanoparticles so they can be mass-produced."

Wanted: Cheaper Fuel Cells

All but a handful of today's electric vehicles run on batteries, which are heavy and can only store so much energy; that's why electric cars have a limited range. Fuel cells are an attractive alternative because they're small and light and could run on a tank full of hydrogen replenished at a fueling station. In addition, the car's exhaust would contain nothing but pure water.

But the catalyst that breaks down oxygen molecules in a requires five to 10 times more platinum than the catalytic converter that scrubs pollutants from conventional engine exhaust. With the price of platinum nearly $1,500 an ounce, running the world's automotive fleet on fuel cells would be prohibitively expensive.

"The number one goal is to minimize how much platinum you use, and you can only realize that goal with nanoparticles," Friebel said. "That's because the catalytic reaction happens only at the surface of the material; and the smaller the particle, the larger the surface area it has with respect to its interior volume."

But the smaller the particles, he said, the more unstable they become. Scientists have combined platinum with other elements, such as nickel, to make catalysts that initially outperformed pure platinum, but later fell behind as the non-platinum part of the alloy corroded away.

About five years ago, SUNCAT Director Jens Nørskov, a theorist who was then at Technical University of Denmark (DTU), and his coworkers suggested that a mixture of platinum and yttrium might do the trick. This seemed like an odd choice; yttrium likes to react with oxygen, which does not bode well for its stability, and the alloy would prove difficult to synthesize. But initial samples made by a company in Germany turned out to be both stable and a decent catalyst.

Testing an Unlikely Combo

To turn the samples into nanoparticles, researchers at DTU bombarded the alloy with argon ions in a vacuum chamber. This knocked out atoms of platinum and yttrium, which cooled and stuck together to form nanoparticles. The scientists sorted the particles by size and discovered that some of the larger ones – about 9 nanometers in diameter – had the best catalytic activity, five times better than today's pure .

Then the scientists examined the nanoparticles with X-ray beams at SLAC's Stanford Synchrotron Radiation Lightsource, a DOE Office of Science user facility, to find out what made them so active. They found that the larger yttrium atoms had escaped from the surfaces of the particles, leaving a surface crust in which the smaller platinum atoms packed together more tightly than usual in a very stable configuration.

For a commercial catalyst, Friebel said, the team will need to find a more efficient way to make the nanoparticles. They'll also see if they can tune the density of the crust so it will perform its tasks of bond-breaking and bond-making to convert oxygen into water even faster.

The 15-member research team included Patricia Hernandez-Fernandez, Ifan E.L Stephens and Ib Chorkendorff at DTU and Anders Nilsson of SUNCAT. Support for this research came from the Danish Ministry of Science, the Danish National Research Foundation, the A.P. Møller and Chastine Mc-Kinney Møller Foundation, the Interdisciplinary Center for Electron Microscopy at EPFL and the DOE Office of Science.

Explore further: Finding answers century-old questions about platinum's catalytic properties

More information: "Mass-selected nanoparticles of PtxY as model catalysts for oxygen electroreduction." Patricia Hernandez-Fernandez,et al. Nature Chemistry (2014) DOI: 10.1038/nchem.2001. Received 03 January 2014 Accepted 10 June 2014 Published online 13 July 2014

Related Stories

SSRL contributes to platinum-based catalyst design

August 15, 2012

(Phys.org) -- Researchers from two SLAC-Stanford joint institutes, the Stanford Institute for Materials and Energy Sciences (SIMES) and the SUNCAT Center for Interface Science and Catalysis, recently joined forces to investigate ...

Researchers develop superior fuel cell material

August 24, 2012

Using a mixture of gold, copper and platinum nanoparticles, IBN researchers have developed a more powerful and longer lasting fuel cell material. This breakthrough was published recently in leading journal, Energy and Environmental ...

'Ordered' catalyst boosts fuel cell output at lower cost

November 1, 2012

(Phys.org)—Fuel cells, which convert fuel directly into electricity without burning it, promise a less polluted future where cars run on pure hydrogen and exhaust nothing but water vapor. But the catalysts that make them ...

New jelly substance could replace platinum in fuel cells

October 7, 2013

(Phys.org) —A substance made from gelatin could be used to replace platinum in fuel cells, according to research published by University of Birmingham scientists in the Royal Society of Chemistry Journal of Materials Chemistry ...

Recommended for you

A new form of real gold, almost as light as air

November 25, 2015

Researchers at ETH Zurich have created a new type of foam made of real gold. It is the lightest form ever produced of the precious metal: a thousand times lighter than its conventional form and yet it is nearly impossible ...

New 'self-healing' gel makes electronics more flexible

November 25, 2015

Researchers in the Cockrell School of Engineering at The University of Texas at Austin have developed a first-of-its-kind self-healing gel that repairs and connects electronic circuits, creating opportunities to advance the ...

Getting under the skin of a medieval mystery

November 23, 2015

A simple PVC eraser has helped an international team of scientists led by bioarchaeologists at the University of York to resolve the mystery surrounding the tissue-thin parchment used by medieval scribes to produce the first ...

Atom-sized craters make a catalyst much more active

November 24, 2015

Bombarding and stretching an important industrial catalyst opens up tiny holes on its surface where atoms can attach and react, greatly increasing its activity as a promoter of chemical reactions, according to a study by ...


Adjust slider to filter visible comments by rank

Display comments: newest first

Jerod McKinley
5 / 5 (1) Jul 22, 2014
Video (Someone took down the video but the article still there) below of what is happening in California at municipal wastewater treatment plants using fuel cell technology to produce 3 value streams of electricity, hydrogen and heat all from a human waste! This is pretty impressive in my opinion for hydro-refueling infrastructure.

"New fuel cell sewage gas station in Orange County, CA may be world's first"


"It is here today and it is deployable today," said Tom Mutchler of Air Products and Chemicals Inc., a sponsor and developer of the project.

2.8MW fuel cell using biogas now operating; Largest PPA of its kind in North America


Microsoft Backs Away From Grid


Hyundai "Tuscon" Fuel Cell Vehicle
$499 per month w/ Free Fuel & Free Maintenance from Hyundai!!! (pure water for exhaust)

Toyota joins California Hydrogen Push in Station Funding - Bloomberg
not rated yet Jul 23, 2014
Why do they continue to fool around with platinum when there are better catalysts out there?


It doesn't have to be good. It merely has to be good enough to be economical.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.