Green-Fueled synthesis of rGO/CuO for catalytic degradation of methyl violet dye

This study presents the green synthesis of copper oxide (CuO) through an eco-friendly solution combustion method, utilizing lemongrass as a natural fuel source. The rGO/CuO composite was prepared via a simple reflux process, emphasizing environmental sustainability. Comprehensive characterization of the synthesized CuO and rGO/CuO composites was conducted using techniques such as XRD, SEM, FTIR, PL, HR-TEM, EDX, and UV–Vis's spectroscopy. The photocatalytic efficiency of the rGO/CuO composite was tested for the degradation of Methyl Violet (MV) dye, achieving an impressive degradation rate of 98.87 ​% and following first-order kinetic behavior. The half-life (t₁/₂) of the reaction was calculated to be 18.17 ​min, with a rate constant (k) of 0.0398 ​min⁻1. Various parameters affecting photocatalytic performance, including pH, dye concentration, light source, and catalyst dosage, were systematically investigated. Scavenger experiments were conducted to determine the active species involved in the degradation process, and total organic carbon (TOC) removal was measured to assess mineralization efficiency. The catalyst's reusability was also evaluated, confirming its potential for long-term use in sustainable environmental remediation applications. Graphical Abstract of Methyl Violet dye degradation in the presence of CuO and rGO/CuO by UV light irradiation. [Display omitted] •CuO nanoparticles synthesized by solution combustion using lemongrass as fuel.•rGO/CuO composite prepared via simple reflux with eco-friendly chemicals.•rGO/CuO achieved 98.84% Methyl Violet degradation, following 1st-order kinetics.•Half-life, pH effect, TOC, quenching, and catalyst recyclability were studied.