New Electric Car Factory in China Produces First ZAP Xebra
Mazda Developing Next Generation RENESIS Rotary Engine

Researchers Develop More Efficient Platinum-Based Catalyst for PEM Fuel Cells

Researchers at the University of Houston have developed a platinum-based catalyst for the cathode side of polymer electrolyte membrane fuel cells (PEMFCs) that is at least four-times and up to six-times more efficient than existing catalysts.

The catalyst material consists of nanoparticles with a platinum-rich shell and a core made of an alloy of copper, cobalt, and platinum. This catalyst demonstrates the highest activity yet observed for the reduction of oxygen.

Peter Strasser, an assistant professor of chemical and biomolecular engineering, leads the group that conducted this research. Their findings are published in the journal Angewandte Chemie.

Platinum-based compounds typically serve as catalyst materials in PEM fuel cells. Platinum, however, is extremely expensive, and the application of the material in fuel cells drives up costs.

The automobile companies have been asking for a platinum-based catalyst that is four-times more efficient, and therefore four-times cheaper, than what is currently available. That’s the magic number.

—Peter Strasser

A PEM fuel cell powerful enough to operate a small two- or four-door automobile would require around 3.33 ounces of platinum costing approximately $3,600, according to Strasser. The use of a catalyst such as the group developed would allow a fuel cell-powered car to operate on about .66 of an ounce of platinum, cutting the cost by almost $3,000.

Strasser and his team deposited an alloy of platinum, copper, and cobalt onto carbon supports in the form of nanoparticles. The active catalytic phase is formed in situ: when a cyclic alternating current is applied to the electrode, the less precious metals, especially the copper, on the surface of the nanoparticles separate from the alloy. This process results in nanoparticles with a core made of the original copper-rich alloy and a shell containing almost exclusively platinum.

The observed increase in surface area of the nanoparticles is not enough to explain the increased activity. Strasser suspects that special altered structural characteristics of the surface play a role. Although the surface consists mostly of platinum, the distances between the platinum atoms on the particle surface seem to be shorter than those in pure platinum. This compression can be stabilized by the alloy core, which shows even shorter Pt-Pt distances because of the presence of copper and cobalt. In addition, the copper-rich core seems to influence the electronic properties of the platinum shell. Theoretical calculations have suggested that the oxygen can thus bind optimally to the particle surface, allowing it to be more easily reduced.

The oxygen-reducing activity of our new electrocatalytic material is unsurpassed—it is four to five times higher than that of pure platinum. In addition, we have demonstrated how to incorporate and activate this material in situ in a fuel cell.

—Peter Strasser

Resources

Comments

jack

A PEM fuel cell powerful enough to operate a small two- or four-door automobile would require around 3.33 ounces of platinum costing approximately $3,600, according to Strasser. The use of a catalyst such as the group developed would allow a fuel cell-powered car to operate on about .66 of an ounce of platinum, cutting the cost by almost $3,000.

Look at that. Researchers took an 83% whack out of a large cost component in one shot.

Amazing what happens when people let the researchers do their work.

AES

I see lots of research being done to refine the catalysts - but what about the PEM itself? AFAIK, the membranes are extremely sensitive to moisture and carbon monoxide levels.

HealthyBreeze

SOFC's are chemically much more robust aren't they? SOFC's big problem seems to be enduring the mechanical stresses of heating up to 700C and cooling again, and the ceramics don't like bouncing around a lot. They could run on wet ethanol, which takes much less energy to distill...seems to me if they were combined with a fast heating coil and a super capicitor, and designed for rapid heating, they might be superior to PEMs. Dunno.

TR

PEM's real advantage is that they are the least-bad option for Fuel Cells in automotive applications. SOFC's would take too long to startup and I'm not certain the packaging would ever get there.

Reducing the Pt for the ORR on the Cathode is a huge part of the cost of a cell - this could represent a good size step in terms of economic viability for PEM's.

Now we just need to ...
1) Increase membrane durability
2) Improve storage and transmission
3) Break the 2nd law of thermodynamics

still much to be done.

itsme

this is a great step forward;

to HealthyBreeze:
1)
storage with quantum 700bar pressure tanks
is already possible at low cost with a larger production volume

2)
no need for transmission if generated on site

3)
:))

Patrick

Does the manufacturing process of the platinum nanoparticles maintain the exact same cost as the original process using platinum? Raw material costs is only one component.

Just because a 100W capable transistor is $20, a bucket of various passive components is $5, various PLLs - VCOs - and microcontrollers may be $10...doesn't mean I can make a high quality 100W home stereo for $35 that will compare to a Harmon Kardon or Onkyo stereo.

Neil

I wonder if this material is any better than the catalyst that they came up with at Argonne labs that increased the activity of the catalyst by an order of magnitude.

There's one problem solved (in the lab) ... PEM durability, hydrogen storage (partially solved) and hydrogen distribution (a matter of big bucks) still to go. Not impossible, just expensive and time consuming. One day these fuel cells will make nice clean range extenders for PHEVs. (where they can operate at a more constant load which will help the PEM to last longer)

A quote from The Toronto Star:
http://www.thestar.com/columnists/article/268851

"(Joseph) Romm, an assistant secretary at the U.S. Department of Energy during the Clinton administration, believes government money funnelled to research and development of hydrogen and fuel cell technologies is a political delay tactic – a way to appear active today by investing in technologies that are forever around the corner."

Jim G.

Romm may be correct, in that Big Three have used the promise of hydrogen to, for instance, justify trashing the EV program. And they've used it to justify delaying mileage improvements. But on the other hand, these fuel cell cars do exist, and the cells have been getting lighter for the same money/power over time.

Tesla automotive is trying to build a business around the idea of an EV as a luxury sports car. It's fascinating the contrast that GM, Ford, etc. present here. They have with access to far more money, are very likely to exist tomorrow. But they don't permit any individual to buy their fuel cell vehicles, at any price. I'd think offering these cars for sale to somebody is one essential piece. Heck, couldn't one of these companies open one or two branded H2 fueling stations inside the county limits of
some of the more massive urban areas, (e.g. Phoenix, LA, Las Vegas, Houston, etc.)? Someone has to get this past the chicken-egg problem if it's to happen at all.

Neil

I'm pretty sure that once the timing suits big oil (when they no longer have access to enough crude) the hydrogen infrastructure will suddenly appear. The only problem is that they'll pass the cost of the infrastructure on to consumers.

Stan Peterson

@jack,

A sage observation.

George

Jack wrote:

Amazing what happens when people let the researchers do their work.

Who's stopping them?

The comments to this entry are closed.