Higher-order porous calcite microspheres exhibiting high specific surface areas, unusual morphologies and textures were fabricated by a simple precipitation reaction of CaCO3 in the presence of PSMA as a crystal modifier.

Mesoporous titanium dioxide nanocrystalline powders were synthesized by ultrasonic-induced hydrolysis reaction of tetrabutyl titanate (Ti(OC4H9)4) in pure water without using any templates or surfactants. The as-prepared samples were characterized with X-ray diffraction (XRD) and N2 adsorption-desorption measurements. The photocatalytic activity of the samples was evaluated using the probe reaction: the photocatalytic oxidation of mixture of formaldehyde and acetone at room temperature. It was found that the as-prepared products by the ultrasonic method were composed of anatase and brooktie phases. The photocatalytic activity of the samples prepared by ultrasonic method is higher than that of commercial Degussa P25 and the samples prepared by conventional hydrolysis method.

Transparent TiO2 nanometer thin films with high photocatalytic activity were prepared on soda-lime glass substrates via the sol-gel method using the TiO2 sol solution. The valency state of Ti element and the chemical compositions in TiO2 thin films were analyzed with X-ray photoelectron spectroscopy (XPS). Experimental results showed that besides Ti, O and C elements there is a small amount of Na and Ca elements diffused from the glass substrates and besides Ti(IV) there is a certain amount of Ti(III) and Ti(II) in TiO2 thin film. Heating temperature of 500 C may be adopted to convert TiO2 gel films into TiO2 (anatase) crystalline films and also the TiO2 (anatase) crystalline films show the highest photocatalytic activity. It was also found that the heat treatment for a suitable time at 500 C improves remarkably the photocatalytic activity of the TiO2 thin film, although for too long a time, rather deteriorates it. These results are explained on the basis of the changes in the surface structure and Ti3C concentration with the heat treatment time.

Sulfur-doped titanium dioxide exhibits a strong visiblelight-induced antibacterial effect. The new photocatalyst can effectively kill Micrococcus lylae, a common Grampositive bacterium. The relationship between sulfur concentration and the bactericidal activity of S-doped TiO2 was investigated. Results from DMPO spin-trapping electron spin resonance measurements confirm the formation of hydroxyl radicals, which is the origin of the considerable bactericidal activity under visible light irradiation.