Biosynthesis of Au–CuO–ZnO Nanocomposite using leaf extract and activity as anti- bacterial, anti-cancer, degradation of CB dye
Authors: Ali Luma Hakim , Muslim Wisam Aqeel , Ghali Azhar Abees , Salem Karrar hazim , Mohammed Kahtan A. , Zabibah Rahman S. , Alkhafaji Mohammed Ayad , Elayaperumal Manikandan , Ameen Noha Inam , Saxena Kuldeep K. 
Published: February 2023

Abstract
The photocatalytic degradation of Cibacron Brilliant Yellow 3G-P (CB) dye in aqueous solution using ZnO, CuO, Au–ZnO, Cu-ZnO, and Au–CuO–ZnO nanomaterials produced using Acacia dealbata leaf extract is described in this study. X-ray diffraction (XRD), Field emission- scanning electron microscopy (FE-SEM), transmission electron microscopic studies (TEM), atomic force microscopy (AFM), element analysis EDX, and diffuse reflectance UV-visible spectroscopy were used to characterize the structural, chemical, morphological, topological, and optical properties of as- synthesized nanomaterials, The characterization research validated the successful synthesis route and demonstrated the effective dispersion of Au and CuO over the ZnO surface. Furthermore, the XRD patterns were discovered to conform to the hexagonal structure of ZnO wurtzite. In addition, A hybrid Au-CuO-ZnO nanocomposite's compositional characterization was explored using EDX-mapping, which proved the efficient distribution of Zn, Cu, O, and Au in the hybrid composite. The roughness of the produced nanostructures was confirmed by topological analysis. With the doping of Au and CuO NPs, the absorption threshold edge of ZnO was moved from the UV to the visible area, according to the optical investigation. Under visible light irradiation, photocatalytic (CB) dye degradation studies demonstrated that the Au–CuO–ZnO nanocomposite is more efficient than pure ZnO at degrading the dye. After 50 minutes After 45 minutes of illumination under ideal circumstances of 1.0 g/L photocatalyst, 10 ppm (CB) dye, and pH 10, photodegradation efficiency of up to 99 percent was achieved. Photogenerated holes and hydroxyl radicals are responsible for the increased photodegradation efficiency of Au–CuO–ZnO, according to the reactive species investigation. The Au-CuO-ZnO nanocomposite displayed high potential stability and recyclability, with 78.6 percent photoactivity remaining after five cycles, according to the recycling data. and study the effect of Au-CuO-ZnO nanocomposite on bacteria of coli Escherichia and Staphylococcus aureus, where these bacteria were used as a representative of the cream negative bacteria and the positive bacteria respectively. The results showed the rate of success (Au-CuO-ZnO nanocomposite) in eliminating and destroying these bacteria and this is possible by using the nanoscale solution to sterilize and eliminate bacteria. By assessing cytotoxicity, it was demonstrated that Au-CuO-ZnO nanocomposite can both kill and stop the proliferation of cancer cells. When compared to cancer cells not treated with the chemical, the Au-CuO-ZnO nanocomposite shown very deadly efficiency against cancer cells by preventing their development and reproduction. One of the most crucial techniques for identifying inhibition in living cells is the procedure of determining the toxicity of the synthesized chemicals. Au-CuO-ZnO nanocomposite had a biological activity with an IC50 of 35.33 g/ml.