Water-splitting technologies could usher in hydrogen economy

June 1 (UPI) --

Researchers at Penn State University have developed a new, cheaper and more efficient way to split water molecule and produce pure hydrogen fuel.

Hydrogen has been promised as the remedy for the world's addiction to fossil fuels. But the fuel isn't cheap or easy to make -- at least not cheap enough to make it an economical substitute for traditional oil and gas fuels.

In addition to being relatively expensive, current methods for hydrogen production are energy intensive and yield unwanted byproducts.

Most industrial hydrogen is made by steam reforming methane. Unfortunately, the production process releases carbon dioxide into the atmosphere, limiting its environmental advantages. Other methods rely on waste heat from alternative energy sources, like solar arrays and nuclear power plants. These methods are more eco-friendly but they're not easily scaled. Some industrial hydrogen is made from water molecules split by a platinum catalyst, but platinum is prohibitively expensive.

Scientists at Penn State set out to find a cheaper catalyst to trigger the water-splitting chemical reactions needed to produce hydrogen. According to a new study published in the journal ACS Nano, they've found one.

The promising new catalyst is an altered form of molybdenum disulfide.

Molybdenum disulfide has been predicted as a possible replacement for platinum, because the Gibbs free energy for hydrogen absorption is close to zero, Mauricio Terrones, a professor of physics, materials science, engineering and chemistry at Penn State, said in a news release.

But molybdenum disulfide is a semiconductor and doesn't conduct electrons efficiently. Researchers amended the material with reduced graphene oxide, an extremely conductive form of carbon. The addition of tungsten made the molybdenum disulfide even more efficient at hydrogen absorption.

Researchers created their new low-energy water splitting catalyst by alternative thin layers of graphene and tungsten-molybdenum disulfide. The catalyst is submerged in a water solution and a small electric current is delivered by an electrode. The catalyst pulls protons from the water, forming a hydrogen bubble that migrates to the surface and is released.