Graphene production by wet chemistry is an ongoing scientific challenge. Controlled oxidation of graphite introduces oxo functional groups; this material can be processed and converted back to graphene by reductive defunctionalization. Although thermal processing yields conductive carbon, a ruptured and undefined carbon lattice is produced as a consequence of CO formation. This thermal process is not understood, but it is believed that graphene is not accessible. Here, we thermally process oxo-functionalized graphene (oxo-G) with a low (4-6 %) and high degree of functionalization (50-60 %) and find on the basis of Raman spectroscopy and transmission electron microscopy performed at atomic resolution (HRTEM) that thermal processing leads predominantly to an intact carbon framework with a density of lattice defects as low as 0.8 %. We attribute this finding to reorganization effects of oxo groups. This finding holds out the prospect of thermal graphene formation from oxo-G derivatives.
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http://dx.doi.org/10.1002/anie.201704419 | DOI Listing |
Chemistry
November 2024
Institute of Chemistry and Biochemistry, Freie Universität Berlin, Altensteinstraße 23a, 14195, Berlin, Germany.
Antioxidants (Basel)
December 2022
School of Chemistry and Materials Science, Ludong University, Yantai 264025, China.
Electrochemical detection can be used to achieve intracellular or in vivo analysis of reduced glutathione (GSH) in tissues such as brain by using a microelectrode, which can help to better understand the complex biochemical processes of this molecule in the human body. The main challenges associated with electrochemical GSH detection are the chemical fouling of electrodes, caused by the oxidation product of GSSG, and biofouling due to the non-specific absorption of biological macromolecules. Oxo-functionalized graphene was generated in situ on the surface of a glassy carbon electrode using a green electrochemical method without using any other modifiers or materials in a mild water solution.
View Article and Find Full Text PDFJ Phys Chem Lett
October 2021
Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 3, 14195 Berlin, Germany.
Heteroatom-doped graphene attracted tremendous attention because of advanced electrocatalytic properties, for example, for oxygen reduction. However, the role of oxygen atoms as heteroatoms in graphene should be explored more deeply. Here, we used statistical Raman spectroscopy for single-layer material analysis and found that the regiochemistry close to vacancy defects plays a decisive role.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2020
Freie Universität Berlin, Institute for Chemistry and Biochemistry, Takustraße 3, 14195, Berlin, Germany.
The thermal decomposition of graphene oxide (GO) is a complex process at the atomic level and not fully understood. Here, a subclass of GO, oxo-functionalized graphene (oxo-G), was used to study its thermal disproportionation. We present the impact of annealing on the electronic properties of a monolayer oxo-G flake and correlated the chemical composition and topography corrugation by two-probe transport measurements, XPS, TEM, FTIR and STM.
View Article and Find Full Text PDFChemistry
May 2020
Institute for Chemistry and Biochemistry, Freie Universität Berlin, Takustraße 3, 14195, Berlin, Germany.
In recent years, graphene oxide has been considered as a soluble precursor of graphene for electronic applications. However, the performance lags behind that of graphene due to lattice defects. Here, the relation between the density of defects in the range of 0.
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