What a load of crap! Graphene from Dog Faeces

14 Aug 2011 | tags: science, graphene

If you’ve read any form of science news over the last few years you are bound to have heard about graphene. Graphene is a single layer of graphite with a structure resembling chicken wire and this results in some fascinating properties including extremely high electrical and thermal conductance. Consequently there’s great interest in graphene for next generation electrical devices (see here for one example). Whether you believe the hype around graphene or not it does have one major drawback, it’s rather expensive to make. One of the best ways of making graphene is micromechanical cleavage of graphite. This is more commonly known as the Scotch tape method as its discoverers (Nobel Prize winners Andre Geim and Kostya Novoselov at Manchester University) used pieces of sticky tape to remove single layers from graphite and transfer it to a silica surface. It doesn’t really need saying but this isn’t really a practical method for making the large quantities of graphene that will be required if it is to be the future of electronics.

The chicken wire lattice structure of graphene

One method for synthesising graphene at an industrially relevant scale is chemical vapour deposition (CVD). Here an appropriate surface (often metals) is placed in a oven with a source of carbon (e.g. methane or a plastic) and heated to high temperature (~1000 °C) at low pressure in the presence of hydrogen. [1] However this still requires the use of expensive sources of carbon. Last week Tour et al. at Rice University have reported that they could synthesise graphene via the CVD method using waste sources of carbon.[2] In their paper they demonstrated successful synthesis using 6 carbon sources:

  • cookies (specifically shortbread flavour)
  • chocolate
  • grass
  • plastic petri dishes
  • a cockroach leg
  • dog faeces

I don’t really want to know what process they used to decide on these sources but it goes without saying that several of these are very cheap (probably free). Although I’d rather not attempt to repeat this work I hope that one day I can publish a paper with an equally odd experimental section.

Growth and Transfer of Graphene Samples. Six different carbon sources were used: Girl Scout cookie (the Girl Scouts of America Troop 25080 from Houston, Texas, provided the cookies, shortbread flavor), chocolate (Chocolate Kennedy Half Dollar Gold Coins), grass (Ophiopogon picked at Rice University), plastic (Fisherbrand polystyrene Petri dishes, catalog #08-757-12), dog feces (Miniature Dachsund), and a cockroach leg (American cockroach caught in a house). The grass and the dog feces were dehydrated in a vacuum oven (102 Torr) at 65 °C for 10 h before being used in the growth process.

[1]  Zhengzong Sun, Zheng Yan, Jun Yao, Elvira Beitler, Yu Zhu & James M. Tour Growth of graphene from solid carbon sources Nature 468, 549–552 (2010) [2]  Gedeng Ruan, Zhengzong Sun, Zhiwei Peng and James M. Tour, _Growth of Graphene from Food, Insects, and Waste _ACS Nano (2011)


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