Nanoscale catalysts for fuel cells

Carnegie Mellon researchers are using nanotechnology to construct a catalyst that makes methanol fuel cells more economical and efficient.

Prashant Kumta, professor of materials science and biomedical engineering, said, "We envision a fuel cell system about the size of a cigarette lighter that could be refuelled by inserting a small cartridge of methanol. So we are essentially developing a more efficient catalyst."

The direct methanol fuel cell is powered by methanol and water. When the methanol and water make contact with a catalyst in the fuel cell, they break down into carbon dioxide, protons and electrons. The protons are attracted by a membrane that allows them to pass through, while blocking the path of the electrons. The electrons must pass through an external circuit to get around the membrane, creating an electrical current. The fuel cell produces carbon dioxide, which is vented away, and water, which can be recycled to use with additional methanol.

"One problem with these fuel cells is that not all the methanol gets properly catalysed and that methanol can seep through the membrane, reducing its efficiency," Kumta said.

Kumta and his group are developing nanostructured catalyst compositions that give improved activity over conventional catalysts. The technology is currently being extended to develop the catalysts on nano-crystalline support systems that will likely exhibit much better reliability and stability compared with present systems, according to Kumta.

These small fuel cells are designed for use in portable electronics, such as mobile phones and laptop computers.

Most methanol fuel cells currently use expensive noble metals like platinum and ruthenium for power. The new design will eliminate these.