Synthesis of Cu-doped ZnO Nanoparticles Using Aloe vera Leaf Extract for Antibacterial and Photocatalytic Activities Evaluation

Background: Fabrication of nanoparticles (NPs) by the biological approach has gained extensive attention recently due to its low cost, simplicity, non-toxic and environmentally-friendly nature, as compared to the toxic as well as expensive chemical and physical methods. This study aimed to synthesize ZnO and Cu-doped ZnO NPs using Aloe vera leaf extract for their photocatalytic and antibacterial activities evaluation. Methods: ZnO and Cu-doped ZnO NPs were synthesized using Aloe vera extract by optimizing the reaction parameters, including precursor salt concentration, plant extract volume, and solution pH. The as-synthesized nanoproducts were characterized using FT-IR, UV-Vis, SEM, and XRD spectroscopic techniques, and tested as antibacterial agents and photocatalysts. Results: The XRD pattern data indicated all the synthesized NPs to have a crystallite nature with a particle size of 19.24 nm, 23.74 nm, and 24.91 nm for ZnO, 1% Cu-doped ZnO, and 4% Cu-doped ZnO NPs, respectively. SEM image revealed crushed-ice, irregular, and spherical shapes of the NPs. The synthesized nanoproducts displayed good antibacterial activity, and the best potential was observed against gram-positive bacteria (B. cereus and S. aureus) of 4% Cu-doped ZnO NPs, followed by 1% Cu-doped ZnO NPs, with the reference to the selected standards gentamicin and DMSO, while the least inhibition zone was seen against gram-negative bacteria (E. coli and S. typhi). 1% Cu-doped ZnO and 4% Cu-doped ZnO displayed good photocatalytic potential at 78.48% and 88.07%, respectively, after 180 min of irradiation, while 4% Cu-doped ZnO NPs displayed better degrading potential with effective reusability. Conclusion: The good antibacterial and photocatalytic activities of the synthesized Cu-doped ZnO NPs may lead to the application of the nanomaterials in antimicrobial and catalysis fields with the required modifications for enhancement of their potential.