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 |