Self-assembly of titanias having surface organic moieties and development of visible-light responsible photocatalytic materials

四异丙醇钛和正硅酸乙酯在1，4-丁二醇中的热反应（糖热法）得到了具有大比表面积和上级热稳定性的纳米晶二氧化硅改性二氧化钛。在本研究中，将所得的二氧化硅改性的二氧化钛在NH_3气流中高温处理，并研究其物理和光催化性能。与未改性的NH_3处理的TiO_2相比，NH_3处理的SiO_2改性的TiO_2在可见光区（400-500 nm）有较强的吸收，在N1s XPS谱中，在396 eV处有较大的吸收峰。这些结果表明，在二氧化硅改性的二氧化钛中稳定地掺杂了更大量的氮。在可见光照射下，所得产物对罗丹明B和乙醛的降解均表现出较高的光催化活性。还通过糖热法制备了各种元素（B、Mg、Al、P、Zn和Ga）改性的纳米TiO 2，并以相同的方式对所得样品进行了氮化。在所考察的六种改性剂中，添加P对可见光照射下乙醛的光催化分解最有效。在氮化和退火之后，P-改性的二氧化钛在可见光区（400-550 nm）显示出强吸收。结果表明，光催化活性与掺杂氮原子的量有关。

Thermal reaction of titanium tetraisopropoxide and tetraethyl orthosilicate in 1,4-butanediol (glycothermal method) afforded nanocrystalline silica-modified titanias having large surface area and superior thermal stability. In this study, the thus-obtained silica-modified titanias were treated in an NH_3 flow at high temperatures, and their physical and photocatalytic properties were investigated. Compared with NH_3-treated TiO_2 without silica modification, the NH_3-treated silica-modified titanias showed a stronger absorption in the visible region (400-500 nm) and had a larger peak at 396 eV in the N 1s XPS spectrum. These results indicate that a larger amount of nitrogen was stably doped in the silica-modified titania. The obtained products exhibited a high photocatalytic activity for degradation of Rhodamine B and decomposition of acetaldehyde under visible light irradiation. Nanocrystalline titanias modified with various elements (B, Mg, Al, P, Zn, and Ga) were also prepared by the glycothermal method and the obtained samples were nitrified in the same way. Among the six modifiers examined, addition of P was the most effective for photocatalytic decomposition of acetaldehyde under visible-light irradiation. After nitrification and annealing, the P-modified titania showed a strong absorption in the visible region (400-550 nm). It was found that the photocatalytic activity was related to the amount of nitrogen atoms doped in the anatase structure.