Tempurung kelapa termasuk sampah organik, sehingga dapat digunakan sebagai sumber karbon alternatif. Grafit merupakan salah satu alotrop karbon yang memiliki struktur mirip sarang lebah yang terdiri dari banyak lapisan, sedangkan grafena hanya memiliki satu lapisan karbon. Untuk mensintesis grafena dapat menggunakan metode sonikasi dengan ukuran partikel grafit +200#, -200+230#, dan -230# serta waktu proses selama 30 dan 60 menit. Grafit didapatkan dari arang tempurung kelapa yang berwarna coklat dan berasal dari perkebunan kelapa di Banten. Setelah proses sonikasi, grafit masuk ke proses hidrotermal dengan dan tanpa gas nitrogen. Grafena oksida yang dihasilkan dikarakterisasi menggunakan Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dan scanning electron microscopy (SEM). Berdasarkan hasil XRD, sampel yang telah sonikasi masih berbentuk grafit oksida. Hal ini didukung dengan hasil SEM yang memiliki morfologi yang berpori dan belum transparan serta tidak terdeteksinya titik 2D pada karakterisasi Raman. Pada karakterisasi FTIR, terdapat ikatan C=C. Berdasarkan karakterisasi Raman, sampel GV 24 menunjukan rasio iD/iG sebesar 0,84. Pada karakterisasi FTIR terdeteksi ikatan O-H, ikatan C-H, dan ikatan C=C. Morfologi permukaan terlihat lebih transparan dari grafit yang telah disonikasi. Berdasarkan karakterisasi Raman, sampel GH 4 menunjukan rasio iD/iG sebesar 0,84. Pada karakterisasi FTIR terdeteksi ikatan O-H, ikatan C=C, dan ikatan C-O. Morfologi permukaan lebih transparan yang menandakan bahwa grafit telah terkelupas. Hasil penelitian menunjukan bahwa semakin lama proses sonikasi dan ukuran partikel -200# +230# menciptakan lapisan yang transparan dan tipis serta menghasilkan grafena oksida setelah melalui proses hidrotermal. Coconut shell is an organic waste and can be used as an alternative carbon source. Graphite is one of the carbon allotropes which has a honeycomb-like structure consisting of many layers, whereas graphene has only single carbon layer. To synthesize graphene, sonication method used by using graphite particle size +200#, -200# +230# and -230#, and processing time of 30 and 60 minutes. Graphite was obtained from brown coconut shell charcoal and comes from coconut plantations in Banten. After the sonication process, graphite processed by hydrothermal method with and without nitrogen gas. Characterization of graphene oxide was done by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Based on the XRD results, the sonicated sample is still in the form of graphite oxide. This is supported by SEM results that have porous morphology and are not transparent and 2D peaks are not detected in Raman characterization. In FTIR characterization, there is a C=C bond. Based on Raman characterization, the GV 24 sample shows an iD/iG ratio of 0.84. In FTIR characterization O-H bonds, C-H bonds, and C=C bonds were detected. Surface morphology looks more transparent than graphite that has been sonicated. Based on Raman characterization, the GH 4 sample shows an iD / iG ratio of 0.84. In FTIR characterization O-H bonds, C=C bonds, and C-O bonds were detected. The surface morphology is more transparent which indicates that the graphite has been peeled off. The results showed that the longer the sonication process and particle size -200# +230# creates a transparent and thin layer and produces graphene oxide after going through the hydrothermal process.