Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Researchers discover less-expensive low-temperature catalyst for hydrogen purification

Left to right: Chemical and Biological Engineering postdoctoral associate Guowen Peng, Professor Manos Mavrikakis, postdoctoral researcher Rahul Nabar, and PhD student Jeff Herron. Photo by Renee Meiller.
Left to right: Chemical and Biological Engineering postdoctoral associate Guowen Peng, Professor Manos Mavrikakis, postdoctoral researcher Rahul Nabar, and PhD student Jeff Herron. Photo by Renee Meiller.

Abstract:
Engineering researchers from Tufts University, the University of Wisconsin-Madison and Harvard University have demonstrated the low-temperature efficacy of an atomically dispersed platinum catalyst, which could be suitable for on-board hydrogen production in fuel-cell-powered vehicles of the future.

Researchers discover less-expensive low-temperature catalyst for hydrogen purification

Madison, WI | Posted on October 1st, 2010

An alternative to copper, which under certain conditions can ignite spontaneously, the platinum-based catalyst is highly active and stable. The researchers' understanding of the structure and function of the new catalyst could help manufacturers design highly effective — but less costly — catalysts on standard, inexpensive support metal oxides.

Led by Maria Flytzani-Stephanopoulos, a Tufts University School of Engineering professor of chemical and biological engineering, and Manos Mavrikakis, a UW-Madison professor of chemical and biological engineering, the research team published its findings in the September 24, 2010, issue of the journal Science.

Only small amounts of hydrogen occur naturally on Earth — yet, according to the U.S. Department of Energy, the country's demand for hydrogen is about 9 million tons per year.

Manufacturers produce about 95 percent of this hydrogen through steam reforming of natural gas, a catalytic process in which steam reacts with methane to yield carbon monoxide and hydrogen. This mixture is known as synthesis gas, or syngas, and is an intermediate in production processes for synthetic fuels, ammonia and methanol, among other compounds.

Another application for hydrogen is fuel for the hydrogen economy, an effort that aims to exploit high-energy-density hydrogen as a cleaner source of energy, particularly for low-temperature fuel-cell-powered devices, including vehicles.

Fuel cells use electrochemical processes to convert hydrogen and oxygen into water, producing direct current that powers a motor. Fuel cell vehicles require highly purified hydrogen, which is produced through a water-gas-shift reaction. This key step strips "residual" carbon monoxide from hydrogen generated through steam reforming of fossil fuels, such as natural gas. Water-gas-shift catalysts decrease the amount of carbon monoxide in hydrogen and increase the hydrogen content by harvesting hydrogen from water molecules.

Catalysts currently used in industry for hydrogen purification are copper-based, supported on zinc oxide and alumina. Because copper is pyrophoric (it could spontaneously ignite when exposed to air; air in fuel cell operation is relatively common), researchers have considered platinum as a substitute. However, platinum is costly and, says Flytzani-Stephanopoulos, researchers must prepare it in very fine particles on more "exotic" supports, such as the rare-earth oxide ceria, which makes it effective for a low-temperature water-gas-shift reaction.

However, while cerium is the most abundant of the rare-earth elements, this natural abundance occurs in just a few places around the world, and, says Mavrikakis, access to it may be limited for various reasons, including geopolitical.

The Tufts researchers initially discovered that sodium improves the platinum activity in the water-gas-shift reaction, which now can take place at low temperatures, even on inert materials like silica. They carried out detailed structural studies and found extra active oxygen species on the surface that helped the platinum complete the reaction cycle. They also found that the sodium or potassium ions helped to stabilize the catalytic site.

In later experiments, they saw their catalyst perform as well as platinum on ceria. Collaborator David Bell of Harvard University used atomic-resolution electron microscopy to view stabilized platinum clusters and atoms on the silica support — visual confirmation that the new catalyst operates like those on ceria supports.

Mavrikakis' team set out to understand why. The researchers drew on powerful computational resources, including the UW-Madison Division of Information Technology and the Center for High-Throughput Computing, as well as an ultrafast 10G data network, to model the new catalyst, atom by atom. "There is no experimental way that you can look at the atoms ‘at work' — that is, while the reaction is happening," says Mavrikakis. "You need to start talking about individual atoms, which you can see with the highest-resolution electron microscopes — but not during the reaction. So you can only suggest that perhaps these atoms are active, but there is no way to substantiate it unless you put an atomic-scale quantum-mechanical model together and come up with a more realistic and well-founded suggestion about what is responsible for making this catalyst so active."

Although platinum is among the most expensive catalytic materials, the new catalyst contains only trace amounts of platinum, yet is robust and effective at low temperatures. Essentially, its structure is a series of small "clusters" comprising only a few atoms, each in a specific arrangement. Each cluster is composed of one or a few a platinum atoms surrounded by a mixture of oxygen, hydroxyl and potassium atoms and is "seated" on the standard aluminum or silica support.

The researchers say the advance is important in part because, through a combination of experiments and first-principles theory, the work reveals a new type of active site for a specific, very important chemical reaction. "Most of the time, people are happy to say, ‘Well, we've found a material. It works for a given application,'" says Mavrikakis.

In this case, says Flytzani-Stephanopoulos, the team took the next step to determine how and why the catalyst works. "If we want to move to the next stage with cheaper materials that are doing the specific chemical transformations, we need to understand the fundamentals," she says.

Other authors on the paper include UW-Madison postdoctoral associate Guowen Peng, PhD student Jeff Herron, and then-PhD students (now alumni) Peter Ferrin and Anand Nilekar; and Tufts University Research Professor Howard Saltsburg, postdoctoral associate Rui Si, PhD student Yanping Zhai and former PhD student Weiling Deng, and master's student Danny Pierre.

The U.S. Department of Energy and National Science Foundation provided primary funding for the research.

####

For more information, please click here

Copyright © University of Wisconsin-Madison

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Enhancing the quantum sensing capabilities of diamond: Shooting electrons at diamonds can introduce quantum sensors into them November 24th, 2017

NanoSummit in Luxembourg: single wall carbon nanotubes have entered our lives as we approach a nanoaugmented future November 23rd, 2017

JPK reports on the exciting research in the School of Medicine at Sungkyunkwan University (SKKU), Suwon, South Korea using the NanoWizard® ULTRA Speed AFM to understand the binding of transcription factor Sox2 with super enhancers November 23rd, 2017

Precision NanoSystems to host nanomedicines roundtable November 23rd, 2017

Chemistry

Dendritic fibrous nanosilica: all-in-one nanomaterial for energy, environment and health November 4th, 2017

Researchers greenlight gas detection at room temperature October 26th, 2017

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

What can be discovered at the junction of physics and chemistry October 6th, 2017

Possible Futures

Enhancing the quantum sensing capabilities of diamond: Shooting electrons at diamonds can introduce quantum sensors into them November 24th, 2017

Fine felted nanotubes : Research team of Kiel University develops new composite material made of carbon nanotubes November 22nd, 2017

Report highlights opportunities and risks associated with synthetic biology and bioengineering November 22nd, 2017

Nano-watch has steady hands November 21st, 2017

Academic/Education

Luleĺ University of Technology is using the Deben CT5000TEC stage to perform x-ray microtomography experiments with the ZEISS Xradia 510 Versa to understand deformation and strain inside inhomogeneous materials November 7th, 2017

Park Systems Announces the Grand Opening of the Park NanoScience Center at SUNY Polytechnic Institute November 3rd, 2017

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Moving at the Speed of Light: University of Arizona selected for high-impact, industrial demonstration of new integrated photonic cryogenic datalink for focal plane arrays: Program is major milestone for AIM Photonics August 10th, 2017

Announcements

Enhancing the quantum sensing capabilities of diamond: Shooting electrons at diamonds can introduce quantum sensors into them November 24th, 2017

NanoSummit in Luxembourg: single wall carbon nanotubes have entered our lives as we approach a nanoaugmented future November 23rd, 2017

JPK reports on the exciting research in the School of Medicine at Sungkyunkwan University (SKKU), Suwon, South Korea using the NanoWizard® ULTRA Speed AFM to understand the binding of transcription factor Sox2 with super enhancers November 23rd, 2017

Precision NanoSystems to host nanomedicines roundtable November 23rd, 2017

Environment

Report highlights opportunities and risks associated with synthetic biology and bioengineering November 22nd, 2017

Dendritic fibrous nanosilica: all-in-one nanomaterial for energy, environment and health November 4th, 2017

Nano-sized gold particles have been shaped to behave as clones in biomedicine November 3rd, 2017

Electrostatic force takes charge in bioinspired polymers November 2nd, 2017

Energy

Inorganic-organic halide perovskites for new photovoltaic technology November 6th, 2017

Dendritic fibrous nanosilica: all-in-one nanomaterial for energy, environment and health November 4th, 2017

New nanomaterial can extract hydrogen fuel from seawater: Hybrid material converts more sunlight and can weather seawater's harsh conditions October 4th, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

Automotive/Transportation

The next generation of power electronics? Gallium nitride doped with beryllium: How to cut down energy loss in power electronics? The right kind of doping November 9th, 2017

Leti Coordinating Project to Develop Innovative Drivetrains for 3rd-generation Electric Vehicles: CEA Tech’s Contribution Includes Liten’s Knowhow in Magnetic Materials and Simulation And Leti’s Expertise in Wide-bandgap Semiconductors October 20th, 2017

GLOBALFOUNDRIES Introduces New Automotive Platform to Fuel Tomorrow’s Connected Car: AutoPro™ provides a full range of technologies and manufacturing services to help carmakers harness the power of silicon for a new era of ‘connected intelligence’ October 12th, 2017

Organic/inorganic sulfur may be key for safe rechargeable lithium batteries October 12th, 2017

Fuel Cells

Hydrogen power moves a step closer: Physicists are developing methods of creating renewable fuel from water using quantum technology September 15th, 2017

More durable, less expensive fuel cells: University of Delaware researchers have developed a new technology that could speed up the commercialization of fuel cell vehicles September 5th, 2017

Engineers pioneer platinum shell formation process – and achieve first-ever observation August 11th, 2017

Argonne National Laboratory’s Continuous ALD Technology Licensed Exclusively to Forge Nano July 7th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project