One of the scientists who discovered graphene is on to yet another major breakthrough involving the wonder material, which has the promise to revolutionise clean energy generation.
In an article published in the latest issue of Nature, a team led by Manchester University physicist Sir Andre Geim described surprising properties of the one-atom thick layer of carbon that could lead to major improvements in fuel-cell technology and even allow harvesting hydrogen from the atmosphere.
In laboratory experiments conducted by Geim and his co-workers, layers of graphene, previously believed to be completely impermeable to all gases and liquids, allowed protons (hydrogen atoms stripped of their electrons) to pass through.
"We are very excited about this result because it opens a whole new area of promising applications for graphene in clean energy harvesting and hydrogen-based technologies," said the study’s co-author Marcelo Lozada-Hidalgo.
The passage of the protons was especially smooth at raised temperatures or if the graphene layer was coated with platinum nanoparticles, acting as a catalyst.
The researchers believe the method, if perfected, could lead to major improvements in fuel-cell technology, cutting cost and enhancing efficiency.
“We worked with small membranes, and the achieved flow of hydrogen is of course tiny so far,” Lozada-Hidalgo explained. “But this is the initial stage of discovery, and the paper is to make experts aware of the existing prospects.”
Hydrogen fuel cells generate electrical energy from a reaction between oxygen and hydrogen. They rely on semi-permeable membranes that allow protons through but block the passage of all other particles.
Despite being known for several decades, the technology still requires major improvements to achieve widespread commercial adoption.
The use of graphene, or its sister material boron nitrate, could help address many shortcomings of the technology including fuel crossover through the existing proton membranes, which reduces the membranes’ efficiency and durability.
Membranes made of graphene, the world’s thinnest and strongest material, could also be much thinner than the ones used currently.
The team has also demonstrated that graphene membranes could be used to extract hydrogen from the atmosphere. If combined with a fuel cell, a mobile electric generator could be created fuelled just by the hydrogen from the air.
“When you know how it should work, it is a very simple set-up,” Lozada-Hidalgo said. “You put a hydrogen-containing gas on one side, apply small electric current and collect pure hydrogen on the other side. This hydrogen can then be burned in a fuel cell.”
According to Lozada-Hidalgo’s colleague Sheng Hu, the technique seems feasible as with today’s technology it is possible to produce very large sheets of graphene.
200 times stronger than steel, graphene was isolated for the first time in 2004 in a Manchaster University lab by Andre Geim and his colleague Konstantin Novoselov. The two researchers were awarded a Nobel Prize in Physics for their discovery in 2010.
Hailed for its sturdiness, enormous flexibility, electric properties and impermeability, graphene is expected to become a real game- changer in many industries. Researchers around the world are studying its potential for flexible thin-film electronics, corrosion-proof coatings, impermeable packaging or even super-thin condoms.