A Novel Route for Producing Graphene Nanosheets from Corncob Using Cassia alata L. Extracts for Electrode and Antioxidant Applications

Developing sustainable and cost-effective strategies for graphene production from renewable resources is crucial for advancing functional materials for energy and biomedical applications. This study introduces a novel and environmentally friendly method for synthesizing graphene nanosheets (GNS) from corncob biomass using Cassia alata L. leaf extract as a green reducing agent. Corncob-derived graphite was initially oxidized to graphene oxide (GO), followed by bio-reduction utilizing phytochemical compounds from C. alata L. leaves. XRD analysis confirmed the structural transformation, showing an increased interlayer spacing from graphite to GO (۰.۸۴۱۵ nm) due to oxygen functionalization, followed by a decrease to ۰.۳۵۸۵ nm in GNS, indicating partial restoration of graphitic order. SEM images revealed a clear morphological evolution—from compact graphite to wrinkled GO sheets, and finally to thin, smooth, overlapping GNS layers. EDS results indicated a substantial reduction in oxygen content after green reduction. FTIR spectra further verified the removal of oxygen-containing functional groups and the re-establishment of sp² carbon networks. UV–Vis analysis showed a red shift in the absorption peak with a decreased bandgap energy from ۳.۲۱ (GO) to ۲.۹۷ eV (GNS), reflecting enhanced electronic conductivity. Electrical measurements confirmed superior charge-transport properties of GNS compared to GO, corncob graphite (CCG), and commercial battery anodes. Antioxidant assays also demonstrated improved radical-scavenging activity of GNS, attributed to its lower bandgap and restored π-conjugated structure. Overall, this work highlights a sustainable approach for converting agricultural waste into high-quality GNS with promising multifunctional applications.

کلیدواژه ها:

Graphene nanosheets ، Corncob biomass ، Green synthesis ، Cassia alata L. extract ، Electrode materials ، Antioxidant activity