Washington, March 1 (IANS): In a pioneering feat, researchers have shown that an inexpensive metal-free catalyst can help us reduce the cost of generating clean energy from polymer electrolyte membrane (PEM) cells.

PEM cells are a type of fuel cell being developed for transport applications as well as for stationary and portable fuel cell applications.

Such a low-cost catalyst can perform the same task earlier carried out by costly metal catalysts.

For nearly half a century, scientists have been trying to replace precious metal catalysts in fuel cells.

"The findings will make low-cost catalysts commercially available, which could, in turn, reduce the cost to generate clean energy from PEM fuel cells," the authors said.

Such cells are mostly used in cars and stationary power plants.

"It is a major breakthrough for commercialisation. This definitely should move the field forward," said Liming Dai, professor of macromolecular science and engineering at the Case Western Reserve University in the US.

The key to the new catalyst is its rationally-designed porous structure.

The researchers mixed sheets of nitrogen-doped graphene, a single-atom thick, with carbon nanotubes and carbon black particles in solution, then freeze-dried them into composite sheets and hardened them.

A fuel cell converts chemical energy into electrical energy by removing electrons from a fuel, such as hydrogen, at the cell's anode, or positive electrode.

This creates current.

Testing showed the porous catalyst performs better and is more durable than the iron-based catalyst.

Efforts are on to fine-tune the materials and structure as well as investigate the use of non-metal catalysts in more areas of clean energy.

The study was published in the journal Science Advances.