A Facile Method for Batch Preparation of Electrochemically Reduced Graphene Oxide.

Yi-Fang Hung,Chia Cheng,Chii-Rong Yang,Chun-Kai Huang

doi:10.3390/nano9030376

Yi-Fang Hung, Chia Cheng + Show 2 more

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https://doi.org/10.3390/nano9030376

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Abstract

The electrochemical reduction of graphene oxide (GO) is an environmentally friendly and energy-saving method for improving the characteristics of GO. However, GO films must be coated on the cathode electrode in advance when usingthis technique. Thus, the formed electrochemically reduced GO (ERGO) films can be used only as sensing or conductive materials in devices because mass production of the flakes is not possible. Therefore, this study proposes a facile electrochemical reduction technique. In this technique, GO flakes can be directly used as reduced materials, and no GO films are required in advance. A 0.1 M phosphate buffered saline solution was used as the electrolyte, which is a highly safe chemical agent. Experimental results revealed that the as-prepared GO flakes were electrochemically reduced to form ERGO flakes by using a −10 V bias for 8 h. The ratio of the D-band and G-band feature peaks was increased from 0.86 to 1.12, as revealed by Raman spectroscopy, the π-π stacking interaction operating between the ERGO and GO has been revealed by UV-Vis absorption spectroscopy, and the C–O ratio was increased from 2.02 to 2.56, as indicated by X-ray photoelectron spectroscopy. The electrical conductivity of the ERGO film (3.83 × 10−1 S·cm−1) was considerably better than that of the GO film (7.92 × 10−4 S·cm−1). These results demonstrate that the proposed electrochemical reduction technique can provide high-quality ERGO flakes and that it has potential for large-scale production.

Highlights

Graphene is a two-dimensional material with a hexagonal honeycomb crystal lattice in which carbon atoms consist of sp2 hybrid orbitals; graphene was discovered by Geim and Novoselov in 2004, who received the 2010 Nobel Prize in physics [1]
The interlayer distance of the electrochemically reduced GO (ERGO) products obtained after electrochemical treatment using a −10 V bias for 2, 4, and 8 h was expected to shrink due to the removal of the oxygenated functional groups [21]
The graphene oxide (GO) and ERGO suspensions had the same concentration of 0.3 g/mL and presented an obvious difference in color before and after the electrochemical reduction

Summary

Introduction

Graphene is a two-dimensional material with a hexagonal honeycomb crystal lattice in which carbon atoms consist of sp hybrid orbitals; graphene was discovered by Geim and Novoselov in 2004, who received the 2010 Nobel Prize in physics [1]. This material has been attracting considerable scientific and technological interest because it has unique physical and chemical properties [2,3,4], such as a large specific surface area, excellent electrical conductivity and thermal conductivity, high mechanical strength, high electron mobility, and visible transparency. GO–RGO materials have a high specific surface area and covalent oxygen functional groups; they can be modified chemically and used in energy storage [17,18] and biosensing [19] applications

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