A Green Synthesis Method to Tune the Morphology of CuO and ZnO Nanostructures

Background: Green synthesis of nanomaterials has gained interest over the years as it has many benefits compared to conventional methods. Green methods are non-toxic and economic due to the use of aqueous extracts as reducing agents. Yerba mate is a widely used herb in South America, showing an available and economical alternative to conventional methods. Methods: Different copper and zinc nanostructures were obtained using yerba mate extract (Ilex paraguariensis) as a reducing and capping agent. Furthermore, adjusting NaCl concentration and temperature, it was possible to successfully tune and examine the morphology of the resulting nanostructures by Scanning Electron Microscopy (SEM). Phenolic oxidation was evaluated by Raman spectroscopy and Fourier Transform Infrared Spectroscopy (FT-IR) to assess the role of yerba mate extract in the reaction. Moreover, antimicrobial activity versus Pseudomonas aeruginosa was assayed, and antioxidant activity was performed by the DPPH method. Results and Conclusion: The present study reveals a powerful method to obtain zinc and copper nanostructures, showing a logarithmic reduction of Pseudomonas aeruginosa of 2.14 and 5.92 CFU/mL at 96 hours respectively and scavenger activity of 42% and 22%, respectively. These properties highlight the potential of the nanomaterials for applications in catalysis, textile, biomedical and agricultural fields.