Synergistic effects of Ag and Cu doping in ZnO: improved photoluminescence, antibacterial, and catalytic performance

This study focuses on the synthesis, characterization, and comparative analysis of pure Zinc Oxide (ZnO), Silver-doped ZnO (Ag-ZnO), Copper-doped ZnO (Cu-ZnO), and silver-Copper co-doped ZnO (Ag-Cu-ZnO) nanomaterials, synthesized via the hydrothermal method. Structural, optical, and antibacterial properties were thoroughly investigated. The average crystallite size was found to be from ~ 22.7 nm to ~ 32.7 nm. UV-Vis spectroscopy indicated improved light absorption in the visible range for doped samples, with the optical band gap decreasing from 3.19 eV for pure ZnO to 3.15 eV (Cu-ZnO), 3.09 eV (Ag-ZnO), and 3.08 eV (Ag-Cu-ZnO). Photoluminescence spectra show dynamic quenching due to the inclusion of metal doping. Antibacterial studies showed improved activity for doped samples compared to pure ZnO. The catalytic activities of these nanomaterials for alcohol oxidation were also assessed, revealing that Ag-Cu-ZnO exhibited the highest catalytic efficiency, achieving complete (100%) conversion of benzoin to benzil with a 90% isolated yield, owing to the combined effects of Ag and Cu ions. Cu-ZnO showed better activity than Ag-ZnO, achieving ~ 87% conversion, but was less effective than the co-doped sample, while pure ZnO displayed the lowest reactivity (~ 72% conversion). These findings emphasize the potential of pristine and doped ZnO nanomaterials for advanced antibacterial and catalytic applications, particularly in environmental remediation.