Process optimization and characterization of green synthesis of Euphorbia hirta reduced graphene oxide

Abstract

Green synthesis of functionalised graphene materials has become one of the pioneering topics in material science lately due to the drawbacks of existing chemical and other synthesis methods. This study focuses on optimising the green synthesis of reduced graphene oxide (rGO) using shoot-derived extracts of Euphorbia hirta and graphene oxide (GO). The approach aims to combine the physicochemical properties of graphene with the bioactivities of plant phytochemicals in the resulting material. Euphorbia hirta plant extract was used to reduce the GO for the first time to the best of our knowledge. We found a straightforward method by optimising the reaction conditions for reduction, enhancing both the practicality and sustainability of the process. Furthermore, the successful reduction of GO to reduced graphene oxide (rGO) production via optimised condition was comprehensively confirmed using the final synthesised material through the X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), and Ultraviolet-visible spectrometer (UV-Vis). The color of the graphene oxide suspension changed from brown to black, as an obvious visible characteristic of the effect of reduction and suggests the formation of rGO. The XRD peak corresponding to GO at 2θ = 10◦ has disappeared, verifying the reduction of GO to rGO. The UV-vis spectra revealed that the synthesis of Euphorbia hirta reduced GO by change in absorption spectrums while the FTIR analysis showed the characteristic oxygen functional groups present in the rGO. Subsequently bioactivities including antioxidant and anti-inflammatory properties are under investigation with the incorporation with plant phytochemicals. Therefore, Euphorbia hirta reduced graphene holds promise in the biomedical field for different applications.