Palladium Nanoparticles May Reduce Cost of Fuel Cells

By Earl Boysen, Nancy C. Muir, Desiree Dudley, Christine Peterson

Laboratories devoted to nanotechnology research are exploring the possibilities of using palladium nanoparticles to reduce the cost of fuel cells and catalytic converters. They have even found that palladium nanoparticles can help clean up organically polluted ground water.

Palladium is an element that can be used as an option to platinum in jewelry and as a catalyst. Palladium has similar properties to platinum but costs about half as much.

In bulk form, palladium is an effective catalyst, though not as effective as platinum. When used as a catalyst, palladium allows the atoms in molecules, such as hydrogen (the hydrogen molecule contains two hydrogen atoms), to bond with its palladium atoms and then releases the hydrogen atoms, allowing them to react with other molecules.

By breaking up molecules into atoms, palladium facilitates chemical reactions and allows them to occur at a lower temperature than they would without a catalyst.

For example, car manufacturers use palladium as a catalyst in the catalytic converter in your car to make air-polluting molecules from your car exhaust less harmful. Using nanoparticles of palladium increases the surface area and percentage of platinum atoms available for contact with molecules involved in the reaction. This lets you get away with smaller quantities of palladium.

Palladium nanoparticles have been shown to be effective catalysts in a variety of chemical reactions. For example, palladium nanoparticles can reduce the amount of platinum that has to be used as a catalyst in fuel cells. Palladium costs roughly half of what platinum costs, which could help reduce the cost of fuel cells.

Researchers have also found that using palladium nanoparticles can improve the performance of a catalyst. In laboratory tests, they found that a fuel cell using a catalyst made with these nanoparticles generated 12 times more current than one containing a catalyst using pure platinum. The fuel cell also lasted ten times longer.

Palladium can also improve the performance of iron nanoparticles used to clean up organic pollutants in groundwater. Adding palladium to iron nanoparticles allows them to contribute more electrons to the reaction, increasing the rate at which chlorinated hydrocarbons such as TCE are degraded.