Integration of noble metals on graphene is renowned for their catalytic and antioxidant prowess. However, utilization of toxic chemicals in the synthesis creates environmental pollution and poisonous nature of chemically synthesized materials. To address this, an economical and eco-friendly method for synthesizing graphene-gold (BRG-Au) nanocomposite by anchoring gold nanoparticles (Au NPs) onto reduced graphene oxide sheets using betel leaf extract as a reducing and stabilizing agent is presented. Comprehensive structural characterizations through UV–Visible, Raman, FT-IR, and XRD analyses confirm the successful formation of the BRG-Au nanocomposite. Morphological assessments utilizing FE-SEM and TEM techniques revealed the presence of transparent, twinkling graphene sheets embellished with 20 to 60 nm of Au NPs in various shapes, including spherical, triangular, pentagonal, circular, and trapezoids. The catalytic and antioxidant activities of the BRG-Au nanocomposite were thoroughly evaluated. In catalytic trials, the nanocomposite exhibited remarkable efficiency in the reduction of 4-nitrophenol to 4-aminophenol, accomplishing this transformation within a mere 30 min during the initial cycle and maintaining stable catalytic performance over three consecutive cycles. Additionally, antioxidant analyses employing Total Antioxidant Activity and 2,2-diphenyl-1-picrylhydrazyl methods demonstrated that BRG-Au nanocomposite possessed equal or superior antioxidant activity than the ascorbic acid standard. This research thus underscores the promising potential of environmentally benign synthesis method for graphene-gold nanocomposite with enhanced catalytic and antioxidant properties.

Green synthesis of graphene using leaf extracts as sustainable reducing and capping agents is a thrust area of research owing to its simplicity, eco-friendly nature and the ease of access to graphene. Moringa (Moringa oleifera Lam) plant is widely cultivated in India owing to its important medicinal and nutritional values. Inspired by these reports, herein we report a simple, green and economic synthesis of graphene, Moringa leaf extract employed reduced graphene oxide (MRGO) with excellent dye removal efficiencies. The MRGO is prepared by refluxing a mixture of aqueous dispersion of graphene oxide and Moringa leaf extract for 10 h. Further, we elucidated the role of synthesized MRGO in the removal of methylene blue (MB) and rhodamine B (RB) dyes through the sonochemical method. This as-synthesized material exhibited excellent dye removal efficiencies of about 93% and 87% against MB and RB dyes, respectively. Graphene with huge surface area expedited the better adsorption of dye molecules, thus, facilitated the better removal of the latter. Therefore, the superior dye removal efficiencies of MRGO were attributed to its adsorption capacity. This cost-effective synthetic approach of MRGO nanomaterial has a great potential for the innovative applications in water purification technology and find its place in further industrialization.