A typical flow of argon gas (99.999 % purity) of 1000 ml/min is used, since earlier investigations at the university showed that this flow favours the formation of solid carbon from ethanol decomposition. An ethanol flow of 2 g/h is chosen - corresponding with 2 vol% ethanol in the vapour/gas mixture - because higher concentrations would result in flame extinction.
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Using this setup, the quality of the resulting graphene is comparable to graphene produced by traditional chemical vapour deposition (CVD) or new graphite exfoliation techniques. However, the scale-up of the current plasma-based technique can be conducted rather easy by connecting several devices in series. The CEM based vaporisation system can replace traditional bubblers, with better performance, stability and accuracy in favour of the former.
The university claims that the technique they use is environmentally friendly because no metal catalysts are needed to activate the graphene growth process. Furthermore, if ethanol is obtained from the fermentation of agricultural processes, it can be considered as a 'clean & green' carbon source.
Download research paper of the University of Cordoba: Scalable graphene production from ethanol decomposition by microwave argon plasma torch.