The growing awareness of green avenues and the use of environmentally friendly technologies for crafting nanostructures leads to a remarkable shift in the fabrication approach. In this scenario, developing a highly crystalline heterojunction catalyst based on metal oxides is seen as a promising strategy. This study investigated the synthesis of nanocomposite La2O3-CeO2-CuO and pure La2O3, CeO2, CuO employing Foeniculum vulgare as a plant extract. The fabricated samples are characterized by X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), Ultraviolet–Visible Spectroscopy (UV-Vis), Transmission Electron Microscopy (TEM), and Energy Dispersive X-ray Analysis (EDAX). The La2O3-CeO2-CuO nanocomposite exhibits remarkable activity against Escherichia coli and Staphylococcus aureus with activity index and zone of inhibition of 93 % (31.90 ±0.15 mm), and 92.33 % (27.7 ±0.12 mm), respectively. Surprisingly, La2O3-CeO2-CuO has a lower band gap, e /h+ recombination, and enhanced charge transfer capability than pure La2O3, CeO2, and CuO. The photodegradation efficiency of La2O3-CeO2-CuO was recorded at 99.7 % after 100 min under sunlight radiation against methylene blue (MB), which was significantly higher than pure La2O3, CeO2, and CuO. Our findings reveal that the La2O3-CeO2-CuO nanocomposite is a highly effective antibacterial agent and photocatalyst formed in conjunction with Foeniculum vulgare as a plant extract. The bi-functionality of La2O3-CeO2-CuO holds signif icant potential in achieving the ultimate clean environment.
