Synthesis and Study of Reduced Graphene Oxide layers under Microwave Irradiation

A variety of oxidation-exfoliation methods have been employed to minimize the restacking effect between the graphene sheets by breaking the van der Waals force, such as chemical treatment, irradiation, thermal annealing and powerful sonication. Each method has its own advantages and disadvantages. Several chemical treatment methods have been developed, but involve harmful reducing agents and are not suitable for mass production. Thermal annealing can produce high quality graphene sheets but it requires a very high temperature of the order of similar to 1050 degrees C. Irradiation and sonication methods serve as pure exfoliation techniques and always require the help of chemical reduction process. In this work an attempt is made to synthesize and study reduced graphene oxide employing low-cost methods. The uniqueness of the present work is the way the Graphite is partially oxidized using aqua regime and dried at 50 degrees C followed by irradiation with microwaves and subsequent exposure to ultrasonic waves to obtain a few layers of reduced grapheme oxide (rGO). Finally, the product thus obtained is dispersed in ethanol and sonicated for 30 minutes using ultra probe sonicator. A stable colloidal dispersion is formed, which is then dried to collect the solid product. The yield to an extent of 65% obtained in this process appears to be promising for commercialization aspects in applications such as energy storage, photovoltaics and opto-electronics devices etc., Morphology (plane and cross-sectional), structure and phase characteristics of the graphene are studied using experimental techniques that include Electron microscopy, Raman scattering, and X-ray diffraction. (c) 2017 Published by Elsevier Ltd.