Experiments reveal unexpected activity of fuel cell...( UPTON NY -- Researchers at the U.S. ...)

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
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