ZnO-based hollow microspheres with mesoporous shells: Polyoxometalate-assisted fabrication, growth mechanism and photocatalytic properties

With the assistance of Keggin-type polyoxometalate, ZnO hollow microspheres with mesoporous shells were synthesized via a simple solvothermal approach without any templates and surfactants. The observations of morphology and structure performed by field emission scanning electronic microscopy and transmission electron microscopy indicated that the shells of the ZnO hollow spheres were built from nanosheets which were composed of nanoparticles. The transformation of structure and composition of samples were investigated by X-ray diffraction, X-ray photoelectron spectrometry and fourier transform infrared absorption spectroscopy. The formation mechanism of the hollow spheres is proposed based on time-dependent experimental results. The ZnO hollow microspheres exhibited a high photocatalytic activity for decolorization of Rhodamine B under ultraviolet irradiation.

Graphical AbstractZnO hollow spheres with mesporous shells were synthesized by an one-pot polyoxometalate-assisted solvothermal route. The ZnO hollow microspheres exhibited a high photocatalytic activity for decolorization of Rhodamine B (RhB) under UV irradiation.Figure optionsDownload as PowerPoint slideHighlights
► ZnO hollow microspheres were synthesized via a solvothermal route with polyoxometalate.
► The polyoxometalate was vital for the formation of the hollow microspheres.
► The ZnO hollow microspheres exhibited excellent photocatalytic activity of Rhodamine B.