We studied the basic properties and fabrication of reduced graphene oxide (rGO) prepared using eco-friendly reduction agents in the graphene solution process. Hydrazine is generally used to reduce graphene oxide (GO), which results in polluting emissions as well as fixed nitrogen functional groups on different defects in the graphene sheets. To replace hydrazine, we developed eco-friendly reduction agents with similar or better reducing properties, and selected of them for further analysis. In this study, GO layers were produced from graphite flakes using a modified Hummer’s method, and rGO layers were reduced using hydrazine hydrate, L-ascorbic acid, and gluconic acid. We measured the particle sizes and the dispersion stabilities in the rGO dispersed solvents for the three agents and analyzed the structural, electrical, and optical properties of the rGO films. The results showed that the degree of reduction was in the order L-ascorbic acid ≥ hydrazine > glucose. GO reduced using L-ascorbic acid had a sheet resistance of 121 kΩ/sq, while that reduced using gluconic acid showed worse electrical properties than the other two reduction agents. Therefore, L-ascorbic acid is the most suitable eco-friendly reduction agent that can be substituted for hydrazine.

Abstract
 1. Introduction
 2. Experimental
  2.1. Preparation of GO and rGO
  2.2. Coating method
  2.3. Characterization
 3. Results and Discussion
 4. Conclusions
 Conflict of Interest
 Acknowledgments
 References

• Young-il Na(School of Advanced Materials Science & Engineering, Sungkyunkwan University)
• Young Il Song(School of Advanced Materials Science & Engineering, Sungkyunkwan University, Advanced Materials and Process Research Center for IT, Sungkyunkwan University)
• Sun Woo Kim(School of Advanced Materials Science & Engineering, Sungkyunkwan University)
• Su-Jeong Suh(School of Advanced Materials Science & Engineering, Sungkyunkwan University, Advanced Materials and Process Research Center for IT, Sungkyunkwan University) Corresponding Author