Green approach to La2O3/ZnO nanocomposites synthesis via Jatropha curcas latex: Implications in photocatalysis

This study presents a comprehensive investigation into the synthesis of zinc oxide (ZnO) nanoparticles and lanthanum oxide (La₂O₃)/ZnO nanocomposites using Jatropha curcas latex, emphasizing a sustainable green chemistry methodology. Characterization techniques, including X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM), and zeta sizer analysis, were employed to elucidate the crystalline structure, optical properties, morphology, and stability of the synthesized materials. The photocatalytic efficacy of the synthesized nanomaterials was rigorously evaluated for the solar-driven photocatalytic removal of methylene blue (MB) dye. Through systematic optimization, an optimal dosage of 3 mg/mL for the La₂O₃/ZnO nanocomposite was identified, demonstrating a significant enhancement in degradation efficiency over ZnO nanoparticles. Under these optimized conditions, the La₂O₃/ZnO catalyst achieved up to 87.71 % removal of MB (initial concentration of 10 mg/L in 100 mL) within 120 min of exposure to natural sunlight. Additionally, under UV irradiation, the MB solution exhibited an exceptional 95.16 % photodegradation, with an estimated rate constant of 0.03224 min⁻¹ after 90 min of treatment with the La₂O₃/ZnO nanocomposite. To further assess the performance and applicability of the photocatalysts, recyclability studies, scavenger studies, and hot filtration tests were conducted, confirming the potential of eco-friendly La₂O₃/ZnO nanocomposites as effective agents for sustainable environmental remediation strategies. This research not only advances the field of photocatalysis but also contributes to the development of sustainable materials for pollution mitigation.