A Novel and Simplest Green Synthesis Method of Reduced Graphene Oxide Using Methanol Extracted Vernonia Amygdalina: Large-Scale Production

Bayisa Meka Chufa,Bedasa Abdisa Gonfa,Teketel Yohannes Anshebo,Getachew Adam Workneh,Da-Ren Hang

doi:10.1155/2021/6681710

Abstract

The large-scale production of high-quality graphene is the major focus of scientists and engineers recently. However, its massive manufacturing routes from its precursor graphene oxide (GO) are involved in the production of toxic gasses and consist of hazardous explosive steps that severely hurt and threaten ecological balance and human health. Therefore, in this study, we investigated the green, effective, and economical approach for the synthesis of graphene by using Vernonia amygdalina (VA) plant leaf extracts for the effective and efficient reduction of GO. The nonexplosive two-step synthesis of GO in a short period of time in the absence of an ice bath was used in this study. The appropriate solvent for the extraction of VA for the green synthesis of graphene was methanol, and the reducing and capping agent in the plant extract was identified to be terpenoids and polyphenols. The graphene/rGO obtained this way was characterized by UV-VIS, XRD, FTIR, SEM, HR-TEM, and EDAX that confirmed the successful reduction of GO to graphene under the hydrothermal process. The HR-TEM images showed the development of few layers of graphene. The FTIR result also shows the complete reduction of GO. Hence, methanol extracted VA leaves consisted of the most appropriate compounds for reducing and capping agent in the green synthesis and could be the preferred method for the large-scale production of graphene-based materials.

Highlights

Graphene, a two-dimensional, only one atom thick, and densely packed crystalline material, is the thinnest, lightest, and strongest material on Earth and the best conductor of heat and electricity known to man [1,2,3,4,5]
Even if the above method and epitaxial chemical vapor depositions are more preferable to produce precise pristine graphene, they are less effective for large-scale manufacturing [11, 12]. e interest of scientists to investigate this material began 70 years ago, when Wallace explained some of the physical properties of graphite through the band theory of solids [13]. e carbon atoms are connected in a hexagonal honeycomb lattice in graphene and can be seen with the naked eye because it absorbs about 2.3% of light [14]
We identified the optimum condition and effective solvent extraction method to be used to extract compounds from Vernonia amygdalina (VA) for the synthesis reduced graphene oxide (rGO)

Summary

Introduction

A two-dimensional, only one atom thick, and densely packed crystalline material, is the thinnest, lightest, and strongest material on Earth and the best conductor of heat and electricity known to man [1,2,3,4,5]. GO is the oxidized analogy of graphene from which we can only synthesize graphene on a large scale [21]. It is a nonstoichiometric chemical compound of carbon, hydrogen, and oxygen in variable ratios which largely depend on the processing methodologies [22,23,24]. GO possesses a large amount of oxygen functional groups that are presented to the carbon skeleton in the form of epoxide and hydroxyl across the basal plane (hydroxyl, carbonyl, and carboxyl) at the edge during chemical oxidation from the oxidizing agent [25,26,27]. GO is highly polar and hydrophilic but is a nonconductor of electricity because of the presence of a large amount of oxygen at its edge and basal plane [31, 32]

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Conclusion