A new sol-gel method was introduced to prepare titanium oxides (TiO2) photocatalytic thin films using peroxide (H2O2) and titanyl sulfate (TiOSO4) as raw materials. The TiOSO4 solution was precipitated by adding ammonia solution, then peptized with 30% H2O2 solution to get a yellow, stable, neutral, and transparent liquid (peroxo titanic complex sol). When the peroxo titanic complex sol was autoclaved above 80℃ for 2h, it changed to a stable, semitransparent sol containing needle-like, ultra-fine anatase crystals less than 20nm in diameter. Titanium oxide (anatase) films used for photocatalysis can be prepared on substrates by a dip-coating technique using peroxo titanic complex and autoclaved sols.

TiO2 photocatalyst were obtained from the hydrolysis product of TiOSO4 with ammonia and the photocatalytic activities were investigated by the photocatalytic degradation of methyl orange aqueous solution under UV-light and visible-light. The results showed that the absorption intensity in visible-light was dependent on the concentration of the materials, pH value and heat-treatment temperature. The color of the TiO2 varied from yellowish to vivid yellow when the TiO2 was calcined at different temperatures from 300℃ to 500℃ for 1h. The photocatalytic activity of TiO2 under visible light was determined by the photo-absorption feature in visible light region, which was related to the heattreatment temperature. The TiO2 calcined at 400℃ shows stronger photo-absorption in visible light region and exhibits higher visible-light activity than the TiO2 calcined at other temperature.

The TiO2 films are prepared by sol-gel method. The tetrabutyl titanate and absolute ethanol are used as raw material and solvent, respectively. Some stabilizing agents are added in the solution to obtain stable sols. By dip-coating, drying, preheating, the TiO2 films on Al2O3 substrates are formed. Then the TiO2-x films are obtained after reducing the TiO2films in H2atmosphere at 1000℃. The value of xdetermined by X-ray diffraction XRD.is between 0 and 0.5. The experiment results show that the TiO2-x films have good oxygen sensitivity and reproducibility when tested in oxidizing-reducing atmosphere at 8008C and excellent resistance–temperature stability in N2 atmosphere.

Cordierite as-recipitated powder was prepared by coating magnesium aluminum hydro-xied powder with an amorphous coating layer from the reaction between magnesium chloride and sodium silicate The coated powder transformaed to amorphous in the range of 500-600℃, and then amorphous silicate crystallized to cristobalite and an intermediate phase appeared at 850℃, a-Cordierited formation in this system is attributed to the reaction between amorphous silicate and a metastable phase of sapphirine, which resulted from the reaction between the crystalline cristobalite and an intermediate phase. The densification of green compacts was not affected by the crystallization of amorphous silicated and intermediate phase because some amorphous silicated remained in the matrix till the temperature of a-cordierite formation.

采用溶腔—凝腔工艺制备了用于汽车新型传感器的氧敏薄膜材料，包括过渡金属氧化物（MoOx、TiOx，CrOx），钙钍矿型（SrTiO3/LaNiO3、LaNiO3，LaCrO3）和类钙钍矿型（Lal-xMxNiO4）纳米粒子薄膜，结果表明，与传统氧传感器用的ZrO2，TiO2半导体材料相比，这三类材料的阻温系数小，敏感度高，响应速度快。