Several calcium titanate samples were prepared by a flux method with various flux salts and various substrate concentration and also by a solid state reaction method. The prepared calcium titanate of various morphologies were loaded with Ag cocatalyst, and examined for the photocatalytic reduction of carbon dioxide with water. A sample prepared with a NaCl flux with a moderate concentration of solute exhibited the highest and stable photocatalytic activity for carbon monoxide production among the prepared samples. It is revealed that the large and flat facets could stabilize the Ag cocatalyst nanoparticles on the surface to enhance the photocatalytic activity for the carbon monoxide production.

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We have found that the dialysis of curdlan dissolved in alkaline solution into aqueous solutions of metal salts yielded multifold gel structures. Aqueous sodium chloride and potassium chloride as well as pure water induced isotropic gels.Aqueous calcium salts induced liquid crystalline gel with refractive index gradient/amorphous gel alternative structure. Aqueous salts of trivalent aluminum and ferric cations induced a rigid liquid crystalline gel, which shrank above a threshold concentration of each salt. On the other hand, Liesegang ring-like pattern was observed with aqueous solutions of mixed salts of calcium chloride and magnesium chloride. The patterns have been classified to discuss the mechanism of forming the variety of structures.

Flux method was applied to prepare sodium hexatitanate (Na 2 Ti 6 O 13) photocatalysts for reduction of carbon dioxide with water. The preparation conditions were examined, such as the starting material, the flux, the composition in the molten mixture, the holding temperature, and the cooling rate of the molten mixture, so as to obtain several sodium hexatitanate samples consisting of the crystals with various morphologies and sizes. These samples were loaded with 0.1 wt% of Ag cocatalyst nanoparticles (Ag/Na 2 Ti 6 O 13) and examined for photocatalytic reduction of carbon dioxide with water, where carbon monoxide, hydrogen and oxygen were formed as products. It was found that the photocatalytic production rate of carbon monoxide varied with the morphology and the size of the sodium hexatitanate crystals. Among the prepared samples, thick rod-like crystals exhibited high photocatalytic activity for the reduction of carbon dioxide.