High quality reduced graphene oxide flakes by fast kinetically controlled and clean indirect UV-induced radical reduction
Journal article, 2016
This work highlights a surprisingly simple and kinetically controlled highly efficient indirect method for the production of high quality reduced graphene oxide (rGO) flakes via UV irradiation of aqueous dispersions of graphene oxide (GO), in which the GO is not excited directly. While the direct photoexcitation of aqueous GO (when GO is the only light-absorbing component) takes several hours of reaction time at ambient temperature (4 h) leading only to a partial GO reduction, the addition of small amounts of isopropanol and acetone (2% and 1%) leads to a dramatically shortened reaction time by more than two orders of magnitude (2 min) and a very efficient and soft reduction of graphene oxide. This method avoids the formation of non-volatile species and in turn contamination of the produced rGO and it is based on the highly efficient generation of reducing carbon centered isopropanol radicals via the reaction of triplet acetone with isopropanol. While the direct photolysis of GO dispersions easily leads to degradation of the carbon lattice of GO and thus to a relatively low electric conductivity of the films of flakes, our indirect photoreduction of GO instead largely avoids the formation of defects, keeping the carbon lattice intact. Mechanisms of the direct and indirect photoreduction of GO have been elucidated and compared. Raman spectroscopy, XPS and conductivity measurements prove the efficiency of the indirect photoreduction in comparison with the state-of-the-art reduction method for GO (hydriodic acid/trifluoroacetic acid). The rapid reduction times and water solvent containing only small amounts of isopropanol and acetone may allow easy process up-scaling for technical applications and low-energy consumption.
1973
Chemistry
functionalization
carbon framework
p1462
aqueous-solution
v69
p5698
1988
solid-state nmr
graphite oxide
Physics
huchmann mn
defects
chemical-reduction
journal of the american chemical society
Science & Technology - Other Topics
rter g
chemistry
acetone
v110
Materials Science
rate constants
journal of the chemical society-faraday transactions i
Author
R. Flyunt
Institut fur Oberflachenmodifizierung Leipzig eV
W. Knolle
Institut fur Oberflachenmodifizierung Leipzig eV
Axel Kahnt
University of Erlangen-Nuremberg (FAU)
C. E. Halbig
University of Erlangen-Nuremberg (FAU)
A. Lotnyk
Institut fur Oberflachenmodifizierung Leipzig eV
T. Haupl
Institut fur Oberflachenmodifizierung Leipzig eV
A. Prager
Institut fur Oberflachenmodifizierung Leipzig eV
Siegfried Eigler
Chalmers, Chemistry and Chemical Engineering
B. Abel
Institut fur Oberflachenmodifizierung Leipzig eV
Nanoscale
2040-3364 (ISSN) 2040-3372 (eISSN)
Vol. 8 14 7572-7579Areas of Advance
Nanoscience and Nanotechnology
Subject Categories
Nano Technology
Chemical Sciences
DOI
10.1039/c6nr00156d