Microstructural and Optical Properties of Green-Synthesized rGO Utilizing <i>Amaranthus viridis</i> Extract

Abstract

Research of green-synthesized reduced graphene oxide (rGO) using Amaranthus viridis (AV) extract has been successfully conducted. The modified Hummers method was used to synthesize graphene oxide (GO), then reduced using hydrazine hydrate and AV extract to obtain rGO. The X-ray diffraction results illustrate the change in crystalline structure from graphite to rGO. Peaks at 2θ angles of 26.5°, 9.1°, and 24.1° indicate the characteristics of graphite, GO, and rGO, respectively. The transmission electron microscopy image shows the formation of 2D nanosheet morphology with slight wrinkles. The fourier transform infrared spectrum represents six peaks of identical functional groups in the graphene-based nanomaterials. Meanwhile, GO has two additional oxygen groups (carboxyl and hydroxyl) at wavenumbers of 1720 cm-1 and 1217 cm-1, respectively. Furthermore, the UV-Vis analysis data shows the typical absorption of GO at 232 nm and 301 nm, while at 266 nm and 278 nm, it belongs to graphite and rGO. The bandgap energy of nanomaterials is 0–3.58 eV, which describes the difference in their optical properties. These promising results reveal the potential of AV as a green-reducing agent to minimize the use of chemicals in the synthesis of rGO for various applications.