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.