Tuning the photocatalytic activity of nanocomposite ZnO nanorods by shape-controlling the bimetallic AuAg nanoparticles

Decorating ZnO with noble metal nanoparticles is a promising strategy for overcoming the rapid recombination of pure ZnO. In this experiment, we evaluated the effects of AuAg nanoflowers (NFl) and AuAg mesopopcorns (MPOPs) on the photocatalytic properties of ZnO (NRs) in comparison with the conventional composite ZnO/Au NPs. ZnO NRs were grown on glass substrate via the ultrasonic spray pyrolysis (USP) and the hydrothermal methods while three types of noble metal particle shapes were synthesized via wet chemical method. The highest degradation percentages of methylene blue (MB) were achieved by the composites ZnO NRs/AuAg NFl, which reached 96% under UV light and 75% under visible light for 300 min. The AuAg NFl were grown in a flower-like shape with petals consisting of AuAg NPs with diameters of 10 nm covering almost the entire surface of ZnO. The photocatalytic performance improvement may be due to bimetallic AuAg in small nanoparticles play a more effective role in O-2 adsorption and have the highest interfacial area, making it easier to transfer free electrons between ZnO and AuAg NFl as well as for O-2 adsorption in the MB solution.

Automated summary

Decorating ZnO with AuAg nanoflowers significantly improved the photocatalytic properties, achieving high degradation percentages of methylene blue. The shape of noble metal nanoparticles also plays a crucial role in enhancing the photocatalytic performance of ZnO.