E.H. Sujiono, A.M.A. Saputra, M. Muchlis, B.D. Usman, N. Nufadilla, N. Azizah, D. Zabrian, Z. Zurnansyah, S. Samnur
Reduced graphene oxide (rGO) derived from coconut shell waste (CS) has been synthesized by varying the ultrasonication time. RGO powders have been characterized using FTIR, XRD, SEM, and UV-Vis spectroscopy. In this study, we divided the ultrasonication time into three variations, namely 2 hours (rGOI), 4 hours (rGOII), and 6 hours (rGOIII). The results of XRD characterization of rGO samples formed two main peaks in the characteristic plane (002) and (100), similar to rGO produced from commercial graphite material. FTIR showed the appearance of a band at 1705 cm-1 associated with the carboxyl (C=O), shifting of the C-OH bond at 1216 cm-1, the band at 1577 cm-1 associated with an aromatic functional group (C=C), and a band at 3431 cm-1 indicates the hydroxyl (-OH) functional group, However, in rGOIII, the hydroxyl group (O-H) is no longer visible (disappearance) and the stretching vibration observed at 1705 cm-1 is also reduced. SEM morphological analysis showed that the rGO material formed pores on the particle surface with pore sizes in the macropore range, each of which had an average pore size diameter of about 1.03 μm (rGOI), 0.61 μm (rGOII), and 1.15 μm (rGOIII), respectively. The UV-Vis results show that the optical properties are quite marked by the spectrum formed due to the light absorption or energy transmitted to the sample. The sample band gap energy values obtained by the Tauc plot method are 4.42 eV for rGOI, 4.78 eV for rGOII, and 4.98 Ev for rGOIII, respectively, which indicate the nature of the semiconductor material and have good potential for electronic device applications. © 2025 American Institute of Physics Inc.. All rights reserved.
Laboratory of Materials Physics, Department of Physics, Universitas Negeri Makassar, Makassar, 90224, Indonesia; Department of Mechanical Engineering, Universitas Negeri Makassar, Makassar, 90224, Indonesia
