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

四异丙氧基钛和正硅酸乙酯在1，4-丁二醇中的热反应(糖热法)得到了具有较大比表面积和良好热稳定性的纳米晶二氧化钛。在本研究中，我们将二氧化硅修饰的二氧化钛在NH_3气流中进行高温处理，并对其物理和光催化性能进行了研究。与未改性的二氧化钛相比，经氨改性的二氧化钛在可见光区(400-500 nm)有较强的吸收，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大量的氮。所得产物在可见光照射下对罗丹明B的降解和乙醛的分解表现出较高的光催化活性。用水热法制备了不同元素(B、Mg、Al、P、Zn、Ga)修饰的纳米二氧化钛，并对所得样品进行了氮化处理。在所考察的六种改性剂中，P的加入对可见光照射下乙醛的光催化降解效果最好。经过硝化和热处理后，P-改性的二氧化钛在可见光区(400-550 nm)有很强的吸收。研究发现，光催化活性与锐钛矿型结构中氮原子的掺杂量有关。

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.