Summary: Chemistry World
Novel chemical approach to graphene
05 July 2009
Researchers in the US have devised a new way to create graphene - sheets of carbon one atom
thick that have extraordinary electronic properties - based upon a detailed understanding of the
chemical structure of an important precursor of the material, graphite oxide.
There are a variety of ways to produce graphene, such as peeling flakes from graphite, but the
challenge is to find a technique that can produce industrial-scale quantities of high-grade material
efficiently. One method uses graphite oxide. In solution the oxide disperses into one-atom-thick
layers, which can be 'spin-coated' onto a surface and then chemically reduced to form graphene.
However, so far it has proved difficult to remove all the oxygen from the sample without introducing
defects into the crystal lattice - and thereby lose some of the properties.
Now, Wei Gao and colleagues at Rice University in Texas have carried out a thorough analysis of
NMR spectroscopic data on graphite oxide to identify the various oxygen structures present within the
material, and then worked out an efficient way to eliminate them by reduction. It was already known
that oxygen occurs in a number of forms in graphite oxide, including hydroxyl, epoxy and ketone
groups. The new work has provided good evidence that previously suspected but unconfirmed
structures are also present in the form of five- and six-membered lactol rings.
Graphene made by a novel reduction strategy