Two birds with one stone: Synthesis of Ag/ZnO composites based on MOF-5 to enhance photothermal antibacterial activity and photocatalytic performance simultaneously

The development of a composite material with superior photothermal and photocatalytic properties holds significant importance in addressing bacterial resistance and organic water pollution. However, the crystal size of zinc oxide and the dispersion of Ag substantially influence the photothermal efficiency and photocatalytic activity of the composite material. In this study, we propose a simple approach for the preparation of Ag/ZnO nanocomposites utilizing MOF-5 as a template and conduct a systematic investigation into their photothermal, antibacterial, and photocatalytic properties. The results indicated that the Ag/ZnO composites possessed a clearly defined structure and demonstrated ​​significant absorption capabilities extending from the visible to the near-infrared light spectrum, indicating their potential as photothermal agents and photocatalyst. The bactericidal efficacy against S. aureus and E. coli reached 100% when the Ag/ZnO concentration was 200 µg/mL using an 808 nm laser (2 W/cm²) for 5 min. The photocatalytic experimental results demonstrate that Ag/ZnO composites exhibit superior catalytic performance compared to pure ZnO. When the adsorption concentration of Ag ions ranges from 0.01 to 0.075 mol/L, Methyl orange dye molecules are nearly completely degraded within 120 min. In addition, the valence band XPS spectra and Fermi levels calculated using the CASTEP code provide insights into the band structures of various photocatalysts. This innovative strategy is beneficial for the design of nanocomposites to effectively solve the problems of drug-resistant bacteria and water pollution, such as organic dyes.