Ruthenium rules for new fuel cells

June 28, 2017, Rice University
Rice University scientists have fabricated a durable catalyst for high-performance fuel cells by attaching single ruthenium atoms to graphene. Credit: Chris Zhang/Rice University

Rice University scientists have fabricated a durable catalyst for high-performance fuel cells by attaching single ruthenium atoms to graphene.

Catalysts that drive the that lets fuel cells turn chemical energy into electricity are usually made of platinum, which stands up to the acidic nature of the cell's charge-carrying electrolyte. But platinum is expensive, and scientists have searched for decades for a suitable replacement.

The -graphene combination may fit the bill, said chemist James Tour, whose lab developed the material with his colleagues at Rice and in China. In tests, its performance easily matched that of traditional platinum-based alloys and bested iron and nitrogen-doped graphene, another contender.

A paper on the discovery appears in the American Chemical Society journal ACS Nano.

"Ruthenium is often a highly active catalyst when fixed between arrays of four , yet it is one-tenth the cost of traditional platinum," Tour said. "And since we are using single atomic sites rather than small particles, there are no buried that cannot react. All the atoms are available for reaction."

Spreading single ruthenium atoms across a sheet of graphene, the atom-thick form of carbon, turned out to be fairly straightforward, Tour said. It involved dispersing graphene oxide in a solution, loading in a small amount of ruthenium and then freeze-drying the new solution and turning it into a foam.

Baking that at 750 degrees Celsius (1,382 degrees Fahrenheit) in the presence of nitrogen and hydrogen gas reduced the graphene and locked nitrogen atoms to the surface, providing sites where ruthenium atoms could bind.

Materials made at higher and lower temperatures weren't as good, and those made at the proper temperature but without either ruthenium or nitrogen proved the quality of the reaction depended on the presence of both.

The material showed excellent tolerance against methanol crossover and in an acidic medium, both of which degrade the efficiency of fuel cells; such degradation is a persistent problem with traditional platinum fuel cells.

Explore further: Cobalt atoms on graphene a powerful combo

More information: "Single-Atomic Ruthenium Catalytic Sites on Nitrogen-Doped Graphene for Oxygen Reduction Reaction in Acidic Medium" ACS Nano (2017). pubs.acs.org/doi/abs/10.1021/acsnano.7b02148

Related Stories

Cobalt atoms on graphene a powerful combo

October 21, 2015

Graphene doped with nitrogen and augmented with cobalt atoms has proven to be an effective, durable catalyst for the production of hydrogen from water, according to scientists at Rice University.

Cheap hybrid outperforms rare metal as fuel-cell catalyst

October 1, 2014

(Phys.org) —Graphene quantum dots created at Rice University grab onto graphene platelets like barnacles attach themselves to the hull of a boat. But these dots enhance the properties of the mothership, making them better ...

Aerogel catalyst shows promise for fuel cells

March 2, 2015

(Phys.org)—Graphene nanoribbons formed into a three-dimensional aerogel and enhanced with boron and nitrogen are excellent catalysts for fuel cells, even in comparison to platinum, according to Rice University researchers.

New catalysts may create more, cheaper hydrogen

August 21, 2007

A new class of catalysts created at the U.S. Department of Energy's Argonne National Laboratory may help scientists and engineers overcome some of the hurdles that have inhibited the production of hydrogen for use in fuel ...

Recommended for you

Nanowires could make lithium ion batteries safer

April 25, 2018

From cell phones and laptops to electric vehicles, lithium-ion batteries are the power source that fuels everyday life. But in recent years, they have also drawn attention for catching fire. In an effort to develop a safer ...

Watching nanomaterials form in 4-D

April 25, 2018

When famed physicists Max Knoll and Ernst Ruska first introduced the transmission electron microscope (TEM) in 1933, it allowed researchers to peer inside cells, microorganisms and particles that were once too small to study.

3 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

rrrander
not rated yet Jun 30, 2017
They would pick one of the most expensive of the platinum group. They can put it with the $5000 worth of airbags in all cars now. Printing money for auto-makers.
Da Schneib
not rated yet Jun 30, 2017
Hmmmm, ruthenium is rarer than platinum; on the other hand, it's not made into jewelry.

We'll see.
Dingbone
Jun 30, 2017
This comment has been removed by a moderator.

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.