Rate and Mechanistic Investigation of Eu(OTf)₂-Mediated Reduction of Graphene Oxide at Room Temperature

Abstract

We describe a fast, efficient, and mild approach to prepare chemically reduced graphene oxide (rGO) at room temperature using divalent europium triflate {Eu(OTf)2}. The characterization of solution-processable reduced graphene oxide has been carried out by various spectroscopic (FT-IR, UV-visible absorption, and Raman), microscopic (TEM and AFM), and powder X-ray diffraction (XRD) techniques. Kinetic study indicates that the bimolecular rate constants for the reduction of graphene oxide are 13.7 ± 0.7 and 5.3 ± 0.1 M(-1) s(-1) in tetrahydrofuran (THF)-water and acetonitrile (ACN)-water mixtures, respectively. The reduction rate constants are two orders of magnitude higher compared to the values obtained in the case of commonly used reducing agents such as the hydrazine derivative, sodium borohydride, and a glucose-ammonia mixture. The present work introduces a feasible reduction process for preparing reduced graphene oxide at ambient conditions, which is important for bulk production of GO. More importantly, the study explores the possibilities of utilizing the unique chemistry of divalent lanthanide complexes for chemical modifications of graphene oxide.

White-Light Emission from Unmodified Graphene Oxide Quantum Dots

“…Natural graphite powder (300 mesh) was purchased from Alfa Aesar and used without further purification. GO was synthesized according the Hummers’ method and characterized as described previously . Concentrated nitric acid (98%), sodium hydroxide, and hydrochloride acid were purchased from Merck Specialties Pvt.…”

“…GO was synthesized by oxidation of natural graphite using a H 2 SO 4 /KMnO 4 /NaNO 3 mixture according to Hummers’ method. The details of the synthesis and characterization of GO were reported in our previous article . GOQDs were synthesized by the oxidative cutting of GO following a literature method with slight modifications .…”

“…GO was synthesized according the Hummers' method and characterized as described previously. 31 Concentrated nitric acid (98%), sodium hydroxide, and hydrochloride acid were purchased from Merck Specialties Pvt. Ltd., Mumbai, India, and utilized without further purification.…”

Photoinduced Electron Transfer from Various Aniline Derivatives to Graphene Quantum Dots

“…GO was prepared according to Hummers’s method, from natural graphite powder, as discussed in our previously published article . GQDs were prepared by a one-step method using GO in DMF according to a literature procedure .…”

A Green Route for Quick and Kilogram Production of Reduced Graphene Oxide and Their Applications at Low Loadings in Epoxy Resins

“…Similar regeneration C=C in rGO has also been reported by Ghosh et. al ., where Eu(OTf) 2 was used for the conversion of GO to rGO at room temperature ,. There is no additional UV absorption for rGO3 as the defect reported in many cases which again ropes the efficacy of the developed approach.…”