Graphene is a 2D carbon allotrope with honeycomb lattice structure. Individual carbon atoms are bonded by sp² hybridization [1] . Graphene has outstanding properties like: excellent electrical and thermal conductivity, flexibility, optical transparency, high specific surface area and much more. These properties make it suitable for various applications, like energy storage and harvesting application (super capacitors, battery, solar cell and so on) [2] - [7] , fabrication of transistors [8] [9] , biomedical application [10] [11] , designing mechanically robust materials [12] [13] [14] [15] etc.

Synthesis of single layer of graphite has been reported as early as in 1975 by B. Lang [16] . After some scattered attempts by various scientist, finally Novoselov et al. have gained the credit for discovery of graphene in 2004 [17] . They introduced a reproducible technique of graphene synthesis by mechanical exfoliation but this technique is not suitable for large scale production. There are some other well established methods also available for synthesis of graphene such as chemical vapour deposition, chemical reduction of graphene oxide and epitaxial growth on silicon carbide.

Currently, many researchers are trying to develop green synthesis methods for graphene production [18] [19] [20] . The purpose of green synthesis process is to use less toxic chemicals and natural precursor. Muramatsu et al. have reported synthesis of graphene from rice husk using KOH and carbon black [20] .

In this research work, we have successfully replaced carbon black by Rice husk itself, in this way, this approach become even more cost effective synthesis methodology. In our synthesis process we have used RHA as carbon source for graphene synthesis and KOH as activation agent. The obtained results have revealed successful synthesis of few layer graphene. Cyclic voltammetry has been performed to evaluate electrochemical performance for energy storage application.

The synthesis process is shown in Figure 1, in typical synthesis process, analytical grade reagent KOH and rice husk were purchased from local market. In typical synthesis process, rice husk collected from local rice mill, was washed several times to remove silica and other contamination as much as possible. After washing, the RHA was prepared by the combustion of rice husk into air. Furthermore, 3 gm of rice husk ash was mixed with 15 gm of KOH and followed by grinding process for 15 min. The mixture of rice husk and KOH was compacted into porcelain crucible. This crucible was covered with ceramic wool and fixed into a larger graphite crucible. The top of the graphite crucible was covered

with sufficient amount of sacrificial RHA to provide a barrier against oxidation of the sample inside porcelain crucible. This sample was annealed at 900˚C for 2 hours in muffle furnace. After this activation treatment, sample was washed several times with distilled water to remove excess KOH and dried at 100˚C for 24 hours.

Synthesized material was characterized by Field emission scanning electron microscopy (FESEM) Zeiss-Ultra Plus, Gemini Co. Transmission Electron Microscopy (TEM) images were obtained using TECNAI G2 20 S-TWIN (FEI Netherlands), X-ray diffraction (XRD) study was done by Bruker AXS Diffractometer D8, Thermal analysis of the synthesized sample was done using Thermogravimetric analysis (TGA) SII 6300 Exstar Instrument from 0 to 820˚C at constant scanning rate of 10˚C/min; Fourier transform infrared spectroscopy (FTIR) by Perkin Elmer, Raman spectroscopy by InviaRenishaw Raman spectrophotometer with Excitation Wavelength of 514 nm Argon ion laser were done. Cyclic voltammetry has been used for electrochemical analysis of the specimen using Basi EC epsilon-EClipse.