Chemists create more efficient palladium fuel cell catalysts

Mar 19, 2009
Brown University researchers have found a way to create a larger active surface area with palladium nanoparticles to catalyze energy-producing reactions in a fuel cell. Credit: Brown University

Even small devices need power, and much of that juice comes from fuel cells. As these devices become even smaller, the rush is on to find more efficient ways to power them.

In the last several years, scientists have discovered that , a metal, is a strong candidate for providing that initial boost that helps fuel cells go. Palladium is far cheaper than another popular , platinum, and it's more abundant.

But researchers have wrestled with creating palladium with enough active to make catalysis efficient in fuel cells while preventing particles from clumping together during the chemical processes that convert a fuel source to electricity. Two Brown University chemists have found a way to overcome those challenges.

The scientists report in the online edition of the that they have produced palladium nanoparticles with about 40 percent greater surface area than commercially available palladium particles. The Brown catalysts also remain intact four times longer than what's currently available.

"This approach is very novel. It works," said Vismadeb Mazumder, a graduate student who joined chemistry professor Shouheng Sun on the paper. "It's two times as active, meaning you need half the energy to catalyze. And it's four times as stable."

Mazumder and Sun created palladium nanoparticles 4.5 nanometers in size. They attached the nanoparticles to a carbon platform at the end of a direct formic acid fuel cell. The researchers then did something new: They used weak binding amino ligands to keep the palladium nanoparticles separate and at the same size as they're attached to the carbon platform. By keeping the particles separate and uniform in size, they increased the available surface area on the platform and raised the efficiency of the fuel cell reaction.

"It just works better," Sun said.

What's also special about the ligands is that they can be "washed" from the carbon platform without jeopardizing the integrity of the separated palladium nanoparticles. This is an important step, Mazumder emphasized, because previous attempts to remove binding ingredients have caused the particles to lose their rigid sizes and clump together, which gums up the reaction.

The Brown team said in experiments lasting 12 hours, their catalysts lost 16 percent of its surface area, compared to a 64-percent loss in surface area in commercial catalysts.

"We managed to ebb the decay of our catalyst by our approach," said Mazumder, who is in his second year in Sun's lab. "We made high-quality palladium nanoparticles, put them efficiently on a support, then removed them from the stabilizers efficiently without distorting catalyst quality."

The Brown scientists now are looking at various palladium-based catalysts with enhanced activity and stability for future fuel cell applications.

"We want to make it cheaper with analogous activity," Mazumder said.

Source: Brown University (news : web)

Explore further: Atom-thick CCD could capture images: Scientists develop two-dimensional, light-sensitive material

add to favorites email to friend print save as pdf

Related Stories

Tiny particles could solve billion-dollar problem

Feb 23, 2005

New research from Rice University's Center for Biological and Environmental Nanotechnology finds that nanoparticles of gold and palladium are the most effective catalysts yet identified for remediation of one of the nation's ...

Peanut-Shaped Nanostructures

Feb 22, 2007

Tiny acorns that fuse together in pairs to form miniature peanuts – Japanese researchers have succeeded in producing peanut-shaped nanoparticles comprised of two different sulfur-containing substances. The ends of the “peanuts” ...

Through the Wire: A New Nanocatalyst Synthesis Technique

Mar 16, 2009

(PhysOrg.com) -- Materials containing bimetallic nanoparticles are attractive in vast technological fields because of their unique catalytic, electronic, and magnetic properties. One of the most promising ...

Recommended for you

The simplest element: Turning hydrogen into 'graphene'

Dec 16, 2014

New work from Carnegie's Ivan Naumov and Russell Hemley delves into the chemistry underlying some surprising recent observations about hydrogen, and reveals remarkable parallels between hydrogen and graphene ...

Future batteries: Lithium-sulfur with a graphene wrapper

Dec 16, 2014

What do you get when you wrap a thin sheet of the "wonder material" graphene around a novel multifunctional sulfur electrode that combines an energy storage unit and electron/ion transfer networks? An extremely ...

User comments : 0

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.