Functional surfaces of carbon materials
Radiation-chemical reduction of graphen oxide
The discovery of graphene is one of the most important events in the chemistry and physics of carbon materials within the last decade. In 2020 more than 50 % of the global market for graphene-based products is expected to be covered by reduced graphene oxide (RedGO) used in the supercapacitors. The most effective route to obtain low cost, good quality graphene in form of highly reduced GO is by means of the reduction of graphene oxide (GO) in its colloidal suspensions.
Drawbacks of commenly used methods include high toxicity and explosivity (hydrazine); too expensive (vitamin C or HI), too long treatment time (40 h for gamma-radiolysis), high reaction temperatures (> 90 ºC), waste management and difficult up-scaling etc. By EB irradiation of aqueous GO solutions highly reducing species like eaq– and H• are produced; additionally strong oxidant •OH radicals can be converted into reducing radicals derived from alcohols with reduction potentials in a wide range (0 to -2.0 V).
Benefits:
- realizable at RT within minutes giving highly quality RedGO (30000 S/m)
- the process is eco-friendly and easily up-scalable
- in contrast to gamma-radiolysis, fast reduction can be achieved even under air
- further modification of RedGO with free-radicals (functionalisation) is possible
Selected Publications
- A. Kahnt, R. Flyunt, S. Naumov, W. Knolle, S. Eigler, R. Hermann, B. Abel
Shedding light on the soft and efficient free radical induced reduction of graphene oxide: hidden mechanisms and energetics
RSC Advances 6 (2016) 68835-68845
DOI:10.1039/c6ra13085b - A. Kahnt, R. Flyunt, C. Laube, W. Knolle, S. Eigler, R. Hermann, S. Naumov, B. Abel
How fast is the reaction of hydrated electrons with graphene oxide in aqueous dispersions?
Nanoscale 7 (2015) 19432-19437
DOI:10.1039/c5nr03444b - R. Flyunt, W. Knolle, A. Kahnt, A. Prager, A. Lotnyk, J. Malig, D. Guldi, B. Abel
Mechanistic Aspects of the Radiation-Chemical Reduction of Graphene Oxide to Graphene-Like Materials
Int. J. Radiat Biol. 90 (2014) 486-494
https://doi.org/10.3109/09553002.2014.907934 - R. Flyunt, W. Knolle, B. Abel, B. Rauschenbach
Verfahren zur Herstellung von reduziertem Graphenoxid sowie damit hergestelltes reduziertes Graphenoxid und dessen Verwendung
Patent DE 10 2012 024 329.4