Researchers Tout Graphene-Iodine Catalyst for Fuel Cells

A metal-free catalyst made of graphene nanoparticles edged with iodine can outperform traditional platinum in fuel cells, according to researchers from Ohio, Texas and South Korea.

The scientists note that a major hurdle in commercializing fuel cells, which "burn" hydrogen to make electricity and water, is the sluggish oxygen reduction reaction at the cathode. Platinum and its alloys are the favored catalyst, but those materials are relatively unstable and prone to degradation.

The scientists from Case Western Reserve, the University of North Texas and the Ulsan National Institute of Science and Technology say their lower-cost catalyst is more stable and can generate one-third more current than platinum. They also claim the material is impervious to poisoning by carbon monoxide and methanol, both of which can hurt the performance of platinum.

The team reported its results earlier this week in the online journal Nature's Scientific Reports.

The researchers make their catalyst in a ball mill that breaks down graphite into graphene microscopic flakes of carbon only one atom thick. The edges of the particles are coated with iodine by introducing the element as a gas during the grinding process.

The resulting material binds with oxygen molecules and simultaneously weakens the bond between the two atoms in each molecule, according to the team, thus facilitating the desired chemical combination of oxygen and hydrogen.

The scientists say electrodes coated with their material can maintain about 86% of their initial current after 10,000 cycles compared with about 63% for a conventional platinum unit. The group is now working to optimize its new catalyst.