Leucaena leucocephala leaves extract mediated green synthesis of TiO2 nanoparticles, characterization and photocatalytic application

Environmental sustainability has become a serious global concern, and to achieve the sustainability goals, we must align our activities with nature by mimicking its processes. Invasive weeds, particularly harmful plant species, serve as nature's reservoirs of phytochemicals, which have significant potential for the eco-friendly fabrication of nanomaterials. The current study focused on the synthesis of versatile TiO₂ nanoparticles (NPs) using aqueous extract of leaves of the Leucaena leucocephala plant and characterized them employing various techniques such as UV-Visible spectrophotometry, FTIR, FESEM-EDS, and XRD. The TiO₂ NPs are prepared in spherical and rhombohedral shapes with smooth surfaces in the anatase phase with high crystallinity and phase purity; the band gap value was estimated to be 2.96 eV, and the crystallite sizes measured using the Scherrer and modified Scherrer methods are 44.79 and 47.52 nm, while considering SEM analysis, it is found to be 57.52 nm, which shows agglomeration of particles. The TiO₂ nanoparticles (NPs) exhibited good photocatalytic activity under visible light, achieving ∼85% degradation of methylene blue (MB) within 120 min, with an apparent rate constant of 0.01257 min⁻¹ . The photocatalyst retained approximately ∼80% of its activity after the fourth reuse cycle, demonstrating moderately good stability and reusability. Furthermore, scavenger studies revealed that hydroxyl (•OH) and superoxide (O₂•⁻) radicals were the dominant reactive species responsible for the photodegradation of MB.