Synthesis of Graphite Oxide with Different Surface Oxygen Contents Assisted Microwave Radiation.

Adriana Ibarra-Hernández,Alejandro Vega-Rios,Velia Osuna

doi:10.3390/nano8020106

Abstract

Graphite oxide is synthesized via oxidation reaction using oxidant compounds that have lattice defects by the incorporation of unlike functional groups. Herein, we report the synthesis of the graphite oxide with diverse surface oxygen content through three (B, C, D) different modified versions of the Hummers method assisted microwave radiation compared with the conventional graphite oxide sample obtained by Hummers method (A). These methods allow not only the production of graphite oxide but also reduced graphene oxide, without undergoing chemical, thermal, or mechanical reduction steps. The values obtained of C/O ratio were ~2, 3.4, and ~8.5 for methodologies C, B, and D, respectively, indicating the presence of graphite oxide and reduced graphene oxide, according to X-ray photoelectron spectroscopy. Raman spectroscopy of method D shows the fewest structural defects compared to the other methodologies. The results obtained suggest that the permanganate ion produces reducing species during graphite oxidation. The generation of these species is attributed to a reversible reaction between the permanganate ion with π electrons, ions, and radicals produced after treatment with microwave radiation.

Highlights

Graphite oxide (GrO) and reduced graphene oxide are interesting materials with potential applications in domains such as photonics and electronic devices, sensors, and energy storage, and as graphene synthesis precursors [1,2,3]
ReTsuhlets GanrOd Dsiasmcupslseisonwith diverse oxygen content were synthesized by three different methTohdeoGlorgOiessaumspinlegs Hwuitmh dmiveresrsme oexthyogden-acsosinstteendt wmeicreroswynatvheesriazdeidatbiyonth(rFeiegduirfefe1re).ntTmheestehopdrooldougicetss uwseinreg cHoummpmareerds mweitthhotdh-eascsGisOtedstmudicyrionwgatvheeracdhieamtiiocnal(Fciogmurpeo1s)i.tiTohnesaenpdrostdruuccttsuwree.rTehceomwpeallr-ekdnwowithn tshyentchGeOsizsetuddmyiantegrtihalebcyhetmheicHalucmommperossimtioetnhaonddisstcraulcletudrceG
Mass ratio used for graphite, sodium nitrate, and potassium permanganate was 1:0.5:3, respectively

Summary

Introduction

Graphite oxide (GrO) and reduced graphene oxide (rGO) are interesting materials with potential applications in domains such as photonics and electronic devices, sensors, and energy storage, and as graphene synthesis precursors [1,2,3]. The graphite oxidation is produced when graphite powder is exposed to strong oxidants. Graphite oxidation was achieved by harsh treatment of one equal weight of graphite powders in concentrated sulfuric acid containing three equal weights of KMnO4 and 0.5 equal weight of NaNO3 [5]. The analysis of the reagents’ stoichiometric quantity on the carbon material oxidation reaction is a preferred strategy for the modified Hummers method [1,2]. The chemical or thermal reduction for the graphene structure partial recovery can be achieved [9,10,11]

Methods

Results

Conclusion