The chemical reduction of graphene oxide is a promising route towards the large scale production of graphene for commercial applications. The current state-of-the-art in graphene oxide reduction, consisting of more than 50 types of reducing agent, will be reviewed from a synthetic chemistry point of view. Emphasis is placed on the techniques, reaction mechanisms and the quality of the produced graphene. The reducing agents are reviewed under two major categories: (i) those which function according to well-supported mechanisms and (ii) those which function according to proposed mechanisms based on knowledge of organic chemistry. This review will serve as a valuable platform to understand the efficiency of these reducing agents for the reduction of graphene oxide.

Chemical reduction of graphene oxide: a synthetic chemistry viewpoint

Background
Graphene holds great promise for potential use in next-generation electronic and photonic devices due to its unique high carrier mobility, good optical transparency, large surface area, and biocompatibility. The aim of this study was to investigate the antibacterial effects of graphene oxide (GO) and reduced graphene oxide (rGO) in Pseudomonas aeruginosa. In this work, we used a novel reducing agent, betamercaptoethanol (BME), for synthesis of graphene to avoid the use of toxic materials. To uncover the impacts of GO and rGO on human health, the antibacterial activity of two types of graphene-based material toward a bacterial model P. aeruginosa was studied and compared.

https://www.dovepress.com/getfile.php?fileID=14605

Oxidative stress-mediated antibacterial activity of graphene oxide and reduced graphene oxide in Pseudomonas aeruginosa

Graphene-family nanomaterials (GFNs) including pristine graphene, reduced graphene oxide (rGO) and graphene oxide (GO) offer great application potential, leading to the possibility of their release into aquatic environments. Upon exposure, graphene/rGO and GO exhibit different adsorption properties toward environmental adsorbates, thus the molecular interactions at the GFN–water interface are discussed. After solute adsorption, the dispersion/aggregation behaviors of GFNs can be altered by solution chemistry, as well as by the presence of colloidal particles and biocolloids. GO has different dispersion performance from pristine graphene and rGO, which is further demonstrated from surface properties. Upon exposure in aquatic environments, GFNs have adverse impacts on aquatic organisms (e.g., bacteria, algae, plants, invertebrates, and fish). The mechanisms of GFNs toxicity at the cellular level are reviewed and the remaining unclear points on toxic mechanisms such as membrane damage are presented. Moreover...

Graphene in the Aquatic Environment: Adsorption, Dispersion, Toxicity and Transformation

Preparation of graphene from chemical reduction of graphene oxide (GO) is recognized as one of the most promising methods for large-scale and low-cost production of graphene-based materials This study reports a new, green and efficient reducing agent (caffeic acid/CA) for GO reduction The CA-reduced GO (CA-rGO) shows a high C/O ratio (715) that is among the best rGOs prepared with green reducing reagents Electronic gas sensors and supercapacitors have been fabricated with the CA-rGO and show good performance, which demonstrates the potential of CA-rGO for sensing and energy storage applications

/pdf/green-preparation-of-reduced-graphene-oxide-for-sensing-and-1psehd40jh.pdf

Green preparation of reduced graphene oxide for sensing and energy storage applications

Chemical reduction of graphene oxide using green reductants

Simultaneous bio-functionalization and reduction of graphene oxide by baker's yeast

A green approach for the electrochemical exfoliation of graphite to graphene is reported. After the exfoliation of graphite, the 9-anthracene carboxylate ion (ACA), which was used as an electrolyte, was adsorbed on the surface of graphene through noncovalent interaction. X-ray diffraction analysis confirms the exfoliation of graphite to graphene. Atomic force microscopy and transmission electron microscopy analyses show the formation of single layer graphene. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy confirm the noncovalent attachment of ACA on the surface of graphene. The 9-anthracene carboxylic acid modified graphene (ACEG) shows good electrochemical performance with a high specific capacitance of 577 F g−1 in 1 M H2SO4. The ACEG electrode shows 83.4% retention in specific capacitance after 1000 charge–discharge cycles. A high coulombic efficiency of 102% is also observed indicating its suitability as energy storage electrode materials.

Electrochemically exfoliated graphene using 9-anthracene carboxylic acid for supercapacitor application

Effects of the reduction of PAni-coated oxidized multiwall carbon nanotubes on the positive temperature coefficient behaviors of their carbon black/high density polyethylene composites

SDBS modified graphene was prepared by electrochemical method using Sodium dodecylbenzenesulfonate (SDBS) as electrolyte and graphite rod as electrode. The anode graphite rod was corroded and deposited at the bottom of the electrolyte solution. The obtained graphene was characterized by Atomic force microscopy (AFM), Raman and Fourier transform infrared spectra (FT-IR). AFM images indicated that most of the layers had the thickness of less than 2 nm, suggesting the fromation of single layer of graphene. The resulting graphene showed very good dispersion stability both in water and in organic solvents (ethanol, acetone).

One-Step Process for the Exfoliation and Surface Modification of Graphene by Electrochemical Method

We fabricated a Li doped CuO photoelectrode by doping CuO with Li to improve the photoelectrochemical properties of the CuO photoelectrode. The fabricated Li doped CuO photoelectrode was optimized by experimentally investigating Li doping concentration, annealing temperature, and spin coating deposition cycle. It was confirmed that Li doped CuO had increased light absorption, decreased energy band gap, and improved crystallinity. The Li-doped CuO photoelectrode had a porous surface, unlike the bare CuO photoelectrode, and had a low charge transfer resistance as well as a high flat band potential. The Li doping concentration experiment demonstrated that the 2 at% Li doped CuO photoelectrode had a superior photocurrent density value compared with a bare CuO photoelectrode. In the annealing temperature optimization experiment with a 2 at% Li doped CuO photoelectrode, it was found to have the best photocurrent density value at 500 oC. In experiments with various spin coating deposition cycles of the Li-doped CuO photoelectrode, the light absorption, energy bandgap, crystallinity, and electrical properties were affected by changes in the film thickness of the photoelectrode. In particular, we confirmed that a sample deposited with 4 spin coating cycles had the lowest interfacial resistance between the photoelectrode and the electrolyte, and the highest flat-band potential value. Consequently, we were able to obtain an improved photocurrent density of -1.68 mA/cm2 compared to the bare CuO photoelectrode using the Li-doped CuO photoelectrode under the optimized conditions of Li 2 at%, an annealing temperature of 500 oC, and 4 cycles of spin coating depositions.

Seon Hyeong Bae

Papers

Simultaneous bio-functionalization and reduction of graphene oxide by baker's yeast

Electrochemically exfoliated graphene using 9-anthracene carboxylic acid for supercapacitor application

Effects of the reduction of PAni-coated oxidized multiwall carbon nanotubes on the positive temperature coefficient behaviors of their carbon black/high density polyethylene composites

One-Step Process for the Exfoliation and Surface Modification of Graphene by Electrochemical Method

Improvement of Photoelectrochemical Properties of CuO Photoelectrode by Li Doping