Engerati has been writing a great deal about the benefits of graphene. While it could be our answer to renewable energy storage [Engerati – Graphene – The Turning Point for Energy Storage?], it could also help generate a new source of energy – from the air.
A recently discovered form of carbon graphite – the material in pencil lead –could revolutionalise the development of clean energy and electric vehicles. Researchers have revealed that graphene allows positively charged hydrogen atoms or protons to pass through it despite being completely impermeable to all other gases, including hydrogen itself. Scientists say that the implications of the discovery are immense as it could dramatically increase the efficiency of fuel cells, which generate electricity directly from hydrogen.
The breakthrough raises the prospect of extracting hydrogen fuel from air and burning it as a carbon-free source of energy in a fuel cell to produce electricity and water, minus the damaging waste products.
“In the atmosphere there is a certain amount of hydrogen and this hydrogen will end up on the other side [of graphene] in a reservoir. Then you can use this hydrogen-collected reservoir to burn it in the same fuel cell and make electricity,” said Professor Sir Andrei Geim of Manchester University.
Graphene – good conductor of electricity
Discovered a decade back, graphene is the thinnest known material but it is 200 times stronger than steel. The material is also the world’s best conductor of electricity.
Until now, being permeable to protons was not considered a practical possibility, but an international team of scientists led by Sir Andrei, who shares the 2010 Nobel Prize for his work on graphene, has shown that the one-atom thick crystal acts like a chemical filter. It allows the free passage of protons but forms an impenetrable barrier to other atoms and molecules.
“There have been three or four scientific papers before about the theoretical predictions for how easy or how hard it would be for a proton to go through graphene and these calculations give numbers that take billions and billions of years for a proton to go through this same membrane,” Sir Andrei said.
“It’s just so dense an electronic field it just doesn’t let anything through. But it’s a question of numbers, no more than that. This makes a difference between billions of years and a reasonable time for permeation.”
The study shows that graphene and a similar single-atom material called boron nitride allowed the build-up of protons on one side of a membrane, yet prevented anything else from crossing over into a collecting chamber.
Creating a new source of clean energy
The researchers say there could be many applications in the field of hydrogen fuel cells and in technology for collecting hydrogen gas from the atmosphere, which would open up a new source of clean energy.
“One of the possibilities we can imagine, however futuristic, which has to be emphasised because everything has been shown on a small scale, is applying a small electric current across the membrane and pushing hydrogen through the graphene or boron nitrite membrane,” he explained.
“Essentially you pump your fuel from the atmosphere and get electricity out of this fuel, in principle. Before this paper, this wouldn’t even be speculation; it would be science fiction. At least our paper provides a guidance and proof that this kind of device is possible and doesn’t contradict any known laws of nature,” Sir Andrei added.