Navigation Links
Experiments reveal unexpected activity of fuel cell catalysts
Date:12/13/2007

UPTON, NY -- Researchers at the U.S. Department of Energys Brookhaven National Laboratory have unveiled important details about a class of catalysts that could help improve the performance of fuel cells. With the goal of producing clean hydrogen for fuel cell reactions in mind, the researchers determined why two next-generation catalysts including gold, cerium, titanium, and oxygen nanomaterials exhibit very high activity. Their results will be published online in the December 14, 2007, edition of the journal Science.

Fuel cells combine hydrogen and oxygen without combustion to produce direct electrical power and water. They are attractive as a source of power for transportation applications because of their high energy efficiency, the potential for using a variety of fuel sources, and their zero emissions. However, a major problem facing this technology is that the hydrogen-rich materials feeding the reaction often contain carbon monoxide (CO), which is formed during hydrogen production. Within a fuel cell, CO poisons the expensive platinum-based catalysts that convert hydrogen into electricity, deteriorating their efficiency over time and requiring their replacement.

Fuel cell reactions are very demanding processes that require very pure hydrogen, said Brookhaven chemist Jose Rodriguez. You need to find some way to eliminate the impurities, and thats where the water-gas shift reaction comes into play.

The water-gas shift (WGS) reaction combines CO with water to produce additional hydrogen gas and carbon dioxide. With the assistance of proper catalysts, this process can convert nearly 100 percent of the CO into carbon dioxide. Rodriguezs group, which includes researchers from Brookhavens chemistry department, the Center for Functional Nanomaterials (CFN), and the Central University of Venezuela, studied two next-generation WGS nanoscale catalysts: gold-cerium oxide and gold-titanium oxide.

These nanomaterials have recently been reported as very efficient catalysts for the WGS reaction, said Brookhaven chemist Jan Hrbek. This was a surprising finding because neither bulk gold nor bulk ceria and titania are active as catalysts.

To determine how these nanocatalysts work, the research team developed so-called inverse model catalysts. The WGS catalysts usually consist of gold nanoparticles dispersed on a ceria or titania surface a small amount of the expensive metal placed on the inexpensive oxide. But to get a better look at the surface interactions, the researchers placed ceria or titania nanoparticles on a pure gold surface.

For the first time, we established that although pure gold is inert for the WGS reaction, if you put a small amount of ceria or titanium on it, it becomes extremely active, Rodriguez said. So although these inverse catalysts are just models, they have catalytic activity comparable to, and sometimes better than, the real deal.

Using a technique called x-ray photoelectron spectroscopy at Brookhavens National Synchrotron Light Source, as well as scanning tunneling microscopy and calculations, the researchers discovered that the catalysts oxides are the reason for their high activity.

The oxides have unique properties on the nanoscale and are able to break apart water molecules, which is the most difficult part of the WGS reaction, Hrbek said. Added Brookhaven physicist Ping Liu: After you dissociate the water, the reaction continues on to eliminate CO. But if you dont have nanosized oxide particles, none of this will work.

The researchers plan to continue their study of these catalysts at the NSLS and CFN in order to further explore the reaction mechanism and optimize its performance.


'/>"/>

Contact: Karen McNulty Walsh
kmcnulty@bnl.gov
631-344-8350
DOE/Brookhaven National Laboratory
Source:Eurekalert

Related biology technology :

1. New Survey Reveals Many Adults With High Cholesterol Fail to Take Necessary Steps to Improve Their Condition
2. Actelion Announces Multiple Presentations on Tracleer(R) and the REVEAL Registry at CHEST 2007
3. New Data Reveal Ethnicity May Play Role in Weight Loss Decisions
4. New paper reveals nanoscale details of photolithography process
5. Stem Cell Agency Finally Reveals Institutions Involved in Conflict Problem
6. Dendreon Announces Publication of Phase 1 Study Highlighting Immunologic and Clinical Activity of Lapuleucel-T (Neuvenge(R)) in Advanced Breast Cancer Patients
7. ANX-514 Reduces Hypersensitivity Reactions Without Impacting Pharmacokinetics or Antitumor Activity in Preclinical Tests
8. Celator(R) Pharmaceuticals Study Shows CPX-571 Maintains Synergistic Ratio of Irinotecan and Cisplatin to Improve Anti-tumor Activity
9. Brostallicin Trial Data Demonstrates Encouraging Anti-tumor Activity in Patients With Chemotherapy-Resistant Cancers
10. Using catalysts to stamp nanopatterns without ink
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:2/16/2017)... -- UCHealth ( Aurora, Colorado ) becomes ... patient management. In addition to optimizing care coordination for ... lung, UCHealth looks to improve provider workflow by decreasing ... Stephanie Brown, RN , Thoracic Nurse Navigator, says, ... Excel spreadsheet, which was extremely arduous and susceptible to ...
(Date:2/16/2017)... 16, 2017  Windtree Therapeutics, Inc. (Nasdaq: ... developing aerosolized KL4 surfactant therapies for respiratory diseases, ... study showed that aerosolized KL4 surfactant reduced lung ... preclinical animal model. The Company believes that these ... evidence that supports the role of KL4 surfactant ...
(Date:2/15/2017)... ... 15, 2017 , ... Executive search firm, Slone Partners, announces ... Matt is a veteran life sciences and molecular diagnostics executive with extensive ... identifying inherited disease risk in future generations. In his new role, Matt will ...
(Date:2/15/2017)... WASHINGTON, Feb. 15, 2017  Vanda Pharmaceuticals Inc. ... results for the fourth quarter and full year ... an exceptional year for Vanda as we continued ... and secured long-term exclusivity for Fanapt," said Mihael ... addition, our emerging pipeline with important 2017 milestones ...
Breaking Biology Technology:
(Date:1/26/2017)... Jan. 26, 2017  Crossmatch, a leading provider of ... solution aimed at combatting fraud, waste and abuse in ... at the Action on Disaster Relief conference in ... for UN agencies and foreign assistance organizations throughout ... and abuse are a largely unacknowledged problem in the ...
(Date:1/24/2017)... 24, 2017  It sounds simple and harmless—an ... monitors vital signs and alerts parents on their ... saturation level drops. But pediatric experts argue that ... with no evidence of medical benefits, especially to ... aggressively to parents of healthy babies, promising peace ...
(Date:1/19/2017)... Calif. , Jan. 19, 2017 ... enhancing user experience and security for consumer electronics, ... next-generation payment processing systems and cybersecurity solutions, today ... banks, enterprises and financial institutions worldwide to bolster ... of the end-to-end secure user authentication platforms they ...
Breaking Biology News(10 mins):