A sustainable strategy to improve photocatalytic degradation properties of CuO and CuO-rGO nanocomposite using Eucalyptus leaf extract

In this study, Copper oxide (CuO) nanoparticles were synthesized using a sustainable approach. The process comprised Eucalyptus leaf extract as both a biological capping agent and a reducing agent. The synthesis process used a one-pot hydrothermal technique to efficiently combine CuO nanoparticles with reduced graphene oxide (rGO). Analytical methods were utilized to investigate the prepared nanocomposite's structural, crystalline, morphological, functional, optical, and thermal characteristics. The prepared sample was analyzed using X-ray diffraction, which revealed that CuO nanoparticles have a monoclinic crystal structure, and no impurity peaks were observed. Field emission scanning microscopes displayed the uniform dispersion of spherical CuO nanoparticles with layered and non-agglomerated, resembling a sponge-like structure of rGO. The microstructural analysis also confirmed the dispersion of copper inside reduced graphene oxide (rGO) sheets. The optical properties, including light absorption and bandgap width, were investigated using UV–visible spectroscopy using bandgap energies of 2.5 and 2.8 eV. In addition, the nanocomposite's ability to degrade cationic Rhodamine 6G and anionic Rose Bengal dyes by photocatalysis was evaluated. The degradation of RB and Rh6G dyes was characterized by nanocatalysis using UV–visible spectroscopy and a pseudo-first-order kinetics model. The pseudo-first-order degradation kinetic rate of Rhodamine 6G was determined to be 2.55 x 10⁻² min⁻¹, indicating that the nanocomposite effectively initiates this dye's degradation. The results showed that dye degradation was effective even at reduced catalyst concentrations.