Platinum-free catalyst could cut cost of hydrogen

The research, published online at the Journal of the American Chemical Society, introduces a new catalyst structure that can facilitate the use of electricity to produce hydrogen gas from water.

Significantly, the catalyst avoids the rare, expensive metal platinum that is normally required for this reaction.

The advantages in efficiency and pollution reduction are so significant that we must push ahead

The material used- molybdenum disulfide- contains two common elements, said Mark Lukowski, a Ph.D. student working with associate professor Song Jin in the UW-Madison chemistry department.

“Most people have tried to reduce the cost of the catalyst by making small particles that use less platinum, but here we got rid of the platinum altogether and still got reasonably high performance.”

The research group has produced milligram quantities of the catalyst, “but in principle you could scale this up,” said Lukowski.

“Molybdenum disulfide is a commercially available product. To control purity and structure, we go through the trouble of synthesizing it from the bottom up, but you could buy it today,” he added.

To make the new material, Lukowski and Jin deposit nanostructures of molybdenum disulfide on a disk of graphite and then apply a lithium treatment to create a different structure with different properties.

When the compound is grown on the graphite, it is a semiconductor, but it becomes metallic after the lithium treatment. Lukowski and Jin discovered that the metallic phase has far greater catalytic properties.

“Even though the efficiency of producing hydrogen has been greatly improved, it is still not as good as what platinum can achieve,” said Jin.

“The next steps include finding ways to further improve the performance by optimizing all aspects of the process and exploring related compounds.

“There are many hurdles to achieving a hydrogen economy, but the advantages in efficiency and pollution reduction are so significant that we must push ahead.”