Scientists predict green energy revolution after new discoveries

Recently discovered wonder-material could have major new applications

A recently discovered form of carbon graphite - the material in pencil lead - has turned out to have a completely unexpected property which could revolutionise the development of green energy and electric cars.

Researchers have discovered that graphene allows positively charged hydrogen atoms or protons to pass through it despite being completely impermeable to all other gases, including hydrogen itself.

The implications of the discovery are immense as it could dramatically increase the efficiency of fuel cells, which generate electricity directly from hydrogen, the scientists said.

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 with no 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 Prof Sir Andrei Geim of Manchester Univeristy.

Ever since its discovery 10 years ago, graphene has astonished scientists. It is the thinnest known material, a million times thinner than human hair, yet more than 200 times stronger than steel, as well as being 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 Andre, 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. There is no magic," he said.

- The Independent