Microwave-assisted hydrothermal synthesis of ZnO rod-assembled microspheres and their photocatalytic performances

ZnO rod-assembled microspheres were successfully fabricated by using the microwave-assisted hydrothermal method in the existence of the poly ethylene glycol (PEG) with the molecular weight of 2000. The structure and morphology of as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The experimental results exhibit that the as-prepared ZnO microspheres with a diameter about 1.5–2.0 μm were composed of many rods with the diameter of 300 nm and the length of 1 μm, respectively. Photoluminescene measurement shows a broad visible emission band centered at around 500–560 nm. The improved catalytic activity may be attributed to structural difference, including morphology, surface orientation and surface defects. Furthermore, the possible growth and photodegradation mechanism of the as-prepared sample is also briefly discussed.