Catalyst boosts gasoline fuel cells

One challenge in making practical high-temperature fuel cells is preventing any carbon contained in the fuel from building up on the cell's anode, or positive contact. One solution has been a separate fuel reformer that converts fuel into pure hydrogen before putting it through the fuel cell.

Researchers from Northwestern University have come up with a catalyst layer that can be put over a conventional anode to reform the fuel within the fuel cell. This allows hydrocarbons like gasoline to be used directly in fuel cells.

The devices could be used to provide auxiliary power in vehicles for lights, radio and heat when a car, truck, automobile or aircraft engine is not running; the method could also eventually be used in hybrid fuel-cell-battery electric cars, according to the researchers.

The researchers' device consists of a thin layer of ruthenium-ceriumdioxide sandwiched by layers of zirconia attached to the surface of the fuel cell anode. Ruthenium-ceriumdioxide speeds the process of extracting hydrogen from hydrocarbon fuel. The researchers also added a small amount of air to the fuel.

The researchers' design uses the high-temperature of solid-oxide fuel cells to power the hydrocarbon-to-hydrogen reaction that generates the hydrogen used to make electricity.

The fuel cell yields power densities of 0.3 to 0.6 watts per square centimeter. Other attempts at using hydrocarbon fuels within solid oxide fuel cells have yielded power densities of 0.1 watts per square centimeter, according to the researchers.

The researchers' prototype uses an idealized iso-octane fuel, and is very small. The researchers' next steps are to adjust the cell so it can use more complex fuels such as gasoline and diesel, and make full-sized fuel cells.

The fuel cell could be used in commercial applications like cars within four years, according to the researchers. The work appeared in the March 31, 2005 issue of Science (An Octane-Fueled Solid Oxide Fuel Cell).