Photon-friendly graphene membranes mimic photosynthesis to produce hydrogen

Researchers at Manchester University have discovered that the rate at which graphene conducts protons increases 10 fold when it is illuminated with sunlight.

Dubbed the “photo-proton” effect, the finding could lead to graphene membranes being used to produce hydrogen from artificial photosynthesis, as well as for light-induced water splitting, photo-catalysis and in photodetectors.

Graphene – a one atom-thick sheet of carbon – is already known to be an extremely good conductor of electrons, and can absorb light of all wavelengths.

But it has also recently been found to be permeable to thermal protons, the nuclei of hydrogen atoms.

To discover how light affects the behaviour of these protons, the researchers fabricated graphene membranes and decorated them on one side with platinum nanoparticles.

When they illuminated the membrane with sunlight, they found the proton conductivity increased by 10 times, according to Dr Marcelo Lozada-Hidalgo, who led the research alongside Prof Sir Andre Geim.

“This is a new effect, it can only be found in graphene, there are no other materials that can use light to produce an enhancement in proton transport,” said Lozada-Hidalgo. “Scientifically this is a new physical phenomenon, which is quite remarkable.”