Gold, copper nanoparticles take center stage in the search for hydrogen production catalysts

Mar 28, 2007

X-ray studies at the U.S. Department of Energy’s Brookhaven National Laboratory are pointing the way to less costly and more efficient catalysts for improving the performance of fuel cells. The studies, which will be presented by Brookhaven chemist Jose Rodriguez at the 233rd National Meeting of the American Chemical Society, show that copper can be substituted for gold in reactions that keep fuel cells functioning longer while eliminating unwanted byproducts.

With the goal of efficient fuel cell operation in mind, researchers first need to turn their attention to hydrogen, which is one of the leading energy sources being investigated by scientists sponsored by the DOE as part of its mission to ensure the nation’s future energy needs.

A major problem facing today’s most promising fuel-cell technologies is that the same hydrogen-rich materials feeding the reaction often contain high levels of carbon monoxide (CO), which is formed during hydrogen production. Within a fuel cell, CO "poisons" the expensive platinum catalysts that convert hydrogen into electricity, deteriorating their efficiency over time and requiring their replacement.

Rodriguez will discuss how the use of gold and copper nanoparticles might provide a solution to this problem on Wednesday, March 28. "We’re trying to find a catalyst that achieves two things: produces hydrogen while removing a large amount of CO," Rodriguez said.

One way to eliminate the CO byproduct is to combine it with water to produce hydrogen gas and carbon dioxide in a process known as the "water-gas shift" reaction. With the assistance of proper catalysts, the water-shift reaction can convert nearly 100 percent of the CO into carbon dioxide. Using catalyst characterization techniques at Brookhaven’s National Synchrotron Light Source (NSLS), Rodriguez and coworkers Jonathan Hanson and Jan Hrbek found that nanoparticles of either gold or copper, supported on a metal, can perform this catalytic role. In particular, they found that the greatest catalytic activity is achieved with extremely small nanoparticles – less than 4 nanometers – supported on the metal cerium oxide, or ceria.

"Metal nanoparticles alone are not able to do the catalysis," Rodriguez said. "But when you put them on the ceria, you see tremendous catalytic activity."

At the nanoscale, gold has long been known to exhibit chemical reactivity that makes it a potent catalyst. The problem, however, comes with its hefty price tag. "We wanted a material that was less expensive," Rodriguez said. "We wanted to see if we could replace the gold with copper." Using x-ray diffraction, absorption, and spectroscopy studies at the NSLS, Rodriguez’s group showed that the substitution is indeed possible. Although gold nanoparticles continue to show the greatest catalytic activity, copper is almost as reactive and its cost is much lower.

Source: Brookhaven National Laboratory

Explore further: Tough foam from tiny sheets

add to favorites email to friend print save as pdf

Related Stories

Hoverbike drone project for air transport takes off

6 hours ago

What happens when you cross a helicopter with a motorbike? The crew at Malloy Aeronautics has been focused on a viable answer and has launched a crowdfunding campaign to support its Hoverbike project, "The ...

Study indicates large raptors in Africa used for bushmeat

7 hours ago

Bushmeat, the use of native animal species for food or commercial food sale, has been heavily documented to be a significant factor in the decline of many species of primates and other mammals. However, a new study indicates ...

'Shocking' underground water loss in US drought

7 hours ago

A major drought across the western United States has sapped underground water resources, posing a greater threat to the water supply than previously understood, scientists said Thursday.

Recommended for you

A new way to make microstructured surfaces

9 hours ago

A team of researchers has created a new way of manufacturing microstructured surfaces that have novel three-dimensional textures. These surfaces, made by self-assembly of carbon nanotubes, could exhibit a ...

Tough foam from tiny sheets

Jul 29, 2014

Tough, ultralight foam of atom-thick sheets can be made to any size and shape through a chemical process invented at Rice University.

Graphene surfaces on photonic racetracks

Jul 28, 2014

In an article published in Optics Express, scientists from The University of Manchester describe how graphene can be wrapped around a silicon wire, or waveguide, and modify the transmission of light through it.

User comments : 0