The Stride Group - Graphene and other Carbon Nanostructures

Graphene

Graphene consists of a single layer of carbon atoms arranged in a periodic chicken wire lattice, and is essentially an isolated single graphitic layer. It was initially isolated by mechanical exfoliation of graphite crystals with sticky tape, but more recently chemical methods have been used to effect chemical exfoliation of graphite. Our approach to producing graphene relies upon a non-graphitic precursor route and allows us to synthesise truly gram-scale quantities in a straight-forward procedure.

gram-scale sample of grapheneTEM images of the fused graphene sheets as produced in a flash pyrolysis processTEM images of the fused graphene sheets as produced in a flash pyrolysis process

Gram-scale sample of graphene (above, left), and TEM images (middle and right) of fused graphene sheets as produced in a flash pyrolysis process.

AFM shows that the sheets can be dispersed upon mild sonication, yielding free sheets of only a single atom thickness (image below).

AFM images showing step heights across a typical sheet to be about 4 Angstroms

AFM images (above) showing step heights across a typical sheet to be 4±1 Å.

We are currently working on potential applications of our sheets, that we hope will include battery and capacitor materials, conductive coatings, gas loading and composite reinforcements.

Nanotubes

Solvothermal synthesis of carbon nanotubes has been published elsewhere1, but there has been little work of carbon nanotube growth in solvothermal conditions without the use of transition metal catalysts. We've been producing these tubes from very simple precursor materials, with repeatability, and without a transition metal catalyst, in very high yields (~80%). Although we have discovered that the transition metal catalyst is not necessary, the tubes produced we believe to be of a more amourphous nature than the traditional crystalline carbon nanotubes. Despite the lack of long range crystal structure, we believe it may have uses in such fields as gas storage, and cheap carbon nanotube reinforced composite material. The tubes grow in highly aligned bundles, and we have observed tubes up to 50µm long. This work has shown commercial promise, and as such, we have submitted a provisional patent2.

Large piece of carbon nanotube product in low (left) and high (right) magnification

Large piece of carbon nanotube product (above), low magnification view (left), allows us to observe pieces >50µm in size while high magnification (right) of the left edge shows that the piece consists of carbon nanotubes.

References

  1. G. Hu, M. Cheng, D. Ma and X. Bao, Chem. Mater., 2003, 15, 1470-1473.
  2. AU Pat., 2008904773, 2008.