A comparative study on coconut shell-derived graphene oxide and reduced graphene oxide

Abstract

Coconut shell (CS) is a waste material with high carbon source potential and is suitable for producing advanced nanomaterials like graphene oxide (GO) and reduced graphene oxide (rGO). However, CS-derived subpar GO and rGO and the lack of comparative studies have restrained their best utilization. This study presents a novel synthesis of high-quality and non-toxic GO and rGO using CS as the precursor, comparing their structural and chemical properties. The synthesis processes involve CS carbonization into graphite, oxidation of graphite into GO using Hummers' method with specific modifications, and non-toxic thermal reduction of GO into rGO. Characterization techniques, including X-ray diffraction, Raman spectroscopy, FTIR, Scanning electron microscopy, and Transmission electron microscopy, confirm successful oxidation and reduction of the samples. Results reveal a well-defined graphitic structure in CS-derived graphite. GO contains oxygen-based functional groups, removed or reduced during thermal reduction. While rGO has fewer defects and restored graphitic arrangement. This study concludes that CS-derived GO and rGO possess desirable properties comparable to those synthesized from pristine graphite, respectively. The results suggest that non-toxic, few-layered, and high-quality GO and rGO synthesized from CS suit biomedical applications, particularly in bone tissue engineering.