Microwave-assisted synthesis of heterostructure Pd/ZnO flowers used for photocatalytic reaction of dyes illuminated by UV radiation

Abstract

Pd nanoparticles loaded on ZnO flowers were successfully synthesized by microwave-assisted deposition method. Phase, morphology, vibrational mode, composition, oxidation state, and specific surface area of heterostructure Pd/ZnO composites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area analysis, field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS). Effect of weight content of the loaded Pd on photodegradation of methylene blue (MB) and methyl orange (MO) illuminated by UV radiation was evaluated. Heterostructure Pd/ZnO composites have photocatalytic efficiency higher than hexagonal ZnO flowers. Schottky Pd/ZnO interface played the role in the charge separation process. In this research, heterostructure 5% Pd/ZnO composites have the highest photodegradation of MB and MO under UV radiation. Main active species of the degradation process and stability of the photocatalyst were investigated. A proposed mechanism for photodegradation of MB and MO was also explained.