Eco-friendly reduction of graphene oxide using urea: An optimized approach for high-performance rGO

The growing demand for environmentally friendly and cost-effective approaches has accelerated the development of sustainable methods for the synthesis of reduced graphene oxide (rGO). In this study, urea was utilized as a green reducing agent for rGO synthesis, offering an alternative to conventional toxic chemicals. The synthesized rGO was comprehensively characterized using FTIR, SEM-EDS, Raman spectroscopy, XRD, BET analysis, zeta potential, and conductivity measurements. These analyses revealed key functional, structural, and morphological properties, including surface functional groups, elemental composition, carbon-to-oxygen (C/O) ratio, particle size (PS), crystallite size (CS), specific surface area (SSA), zeta potential (ZP), thermal conductivity (TC), and electrical conductivity (EC). Process optimization was performed using the Taguchi L4(23) orthogonal array design across nine quality parameters. Under optimal conditions, notable enhancements were achieved: C/O ratio increased by 108%, ID/IG ratio by 164%, I2D/IG ratio by 26%, CS by 75%, and SSA by 134%, while PS was reduced by 37%. Furthermore, ZP and TC increased by 58% and 33%, respectively, whereas EC was reduced by 97%. These findings demonstrate the potential of urea as a sustainable and effective reducing agent in the production of high-performance rGO materials.