Three-dimensional TiO 2 microspheres with different hierarchical nanostructures were synthesized by the synergistic strategies of ultrafast electrochemical spark discharge spallation process followed by thermal treatment. The morphology, crystal structure, surface area, and photocatalytic activity of the hierarchical nanostructures were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, surface area analysis, and UV−vis spectroscopy respectively. The nanostructure of hierarchical microspheres undergoes three evolution steps, which includes the change from nanosheets into hybrid nanoflakes/ nanoparticles and finally to nanoparticles as calcination temperature increases, in line with the predicable trend of increase in crystallinity and decrease in specific surface area. Compared to other forms of calcined TiO 2 samples (nanosheets and nanoparticles), the hybrid TiO 2 nanoflake/ nanoparticle hierarchical porous structure exhibits a higher photocatalytic activity for the degradation of organic compounds (methyl orange and bisphenol A). This is attributed to their larger specific surface area (∼116 m 2 /g), more abundant porosity, and good crystallinity. On the basis of this hybrid structure, a visible light sensitive Ag/TiO 2 microsphere photocatalyst is designed which shows faster degradation rate under the visible light illumination (>420 nm). The porous microspheric photocatalyst does not lose its activities after recycled use, showing great potential for practical application in environmental cleanup.

Floating polymeric microcapsules that simultaneously entrap multiple drugs were prepared using a solid/water/oil/water emulsion solvent evaporation method, based on harnessing interfacial phenomena and manipulation of the solvent removal process. The fabricated microcapsules exhibited excellent buoyancy in simulated gastric fluid and provided controlled and sustained release of multiple drugs for up to 24 h, thus revealing their potential as a ratecontrolled oral drug delivery system.

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