Graphene, impermeable to all gases and liquids, can easily allow protons to pass through it, University of Manchester researchers have found.
Published in the journal Nature, the discovery could revolutionize fuel cells and other hydrogen-based technologies as they require a barrier that only allow protons - hydrogen atoms stripped off their electrons - to pass through.
In addition, graphene membranes could be used to sieve hydrogen gas out of the atmosphere, where it is present in minute quantities, creating the possibility of electric generators powered by air.
One-atom thick material graphene, first isolated and explored in 2004 by a team at The University of Manchester, is renowned for its barrier properties, which has a number of uses in applications such as corrosion-proof coatings and impermeable packaging.
For example, it would take the lifetime of the universe for hydrogen, the smallest of all atoms, to pierce a graphene monolayer.
Now a group led by Sir Andre Geim tested whether protons are also repelled by graphene. They fully expected that protons would be blocked, as existing theory predicted as little proton permeation as for hydrogen.