Hollow microspheres were coated by titanium dioxide via the surface sol-gel pretreatment and the hydrothermal method. Obtained products were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), etc. Effects of varied process parameters were explored on the morphology and structure of products. Experimental results showed that the surface sol-gel pretreatment played a critical role in the following hydrothermal reaction. By first treating the hollow microsphere surface using the surface sol-gel process followed by the hydrothermal reaction under appropriate conditions, we successfully coated hollow microspheres with close-packed anatase nanorods perpendicular to the surface of hollow microsphere. These materials are light-weighted and corrosion-resistant, and are expected to become a new type of photocatalyst that holds promise in abatement of organic pollutants on large-area surface waters.

Key words: surface sol-gel process, hydrothermal synthesis, hollow microsphere, coating, titanium dioxide