Near Green Synthesis of Porous Graphene from Graphite Using an Encapsulated Ferrate(VI) Oxidant

Abstract

Graphene oxide (GO) is a conventional yet vital precursor for the synthesis of porous graphene (PG). Several strong oxidizing agents such as potassium permanganate and perchlorates are typically used for oxidization of graphite. However, they expose toxic reactants/products that harm the environment. Therefore, a greener approach is desperately needed to oxidize and exfoliate graphite. This study reports for the first time on successful oxidation of graphite by ferrate(VI) compounds via an encapsulation approach. By further reducing GO prepared from this near green route with vitamin C, PG anticipated by many highly important and expanding areas such as water treatment could be readily achieved. X-ray diffraction (XRD), Fourier transform infrared (FTIR) and UV-vis spectroscopy, and scanning electronic microscopy (SEM) along with energy-dispersive spectroscopy confirmed the high yield of GO from the oxidation of graphite. Raman spectroscopy, XRD, and TEM confirmed the formation of high-quality few-layered PG from the reduction of as-prepared GO. The above results demonstrated the practicality of using encapsulated ferrate(VI) compounds to realize green oxidation of graphite and resolve the paradox about the oxidation capability of ferrate(VI). To further illustrate its potential for the removal of emerging and crucial contaminants from water, as-prepared PG was further examined against the contaminants of methyl orange (MeO) dye and ibuprofen (IBU). Taken together, the results revealed that more than 90% removal efficiency could be achieved at a high PG dosage against MeO and IBU. This ground-breaking greener approach opens the door to risk-free, extensive graphene environmental applications.