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

Abstract

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. 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. 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. 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.