Creation of super high performance photocatalyst by control of nanomicrostructure of titanium oxide

以四异丙氧钛(TTIP)为原料，加入不同的二聚氰胺，采用Sol-Gel法制备了不同种类的二氧化钛。以1，3-丁二醇和乙二醇制得的钛(OCH_2CH_20)_2为原料，成功地合成了高结晶度的前驱体Ti(OCH(CH_3)CH_2CH2O)_2。特别是1，3-丁二醇烷氧基二酸钛在346时发生了剧烈的分解，并转变为方棒状的TiO2相。前驱体在空气中于5 0 0μ条件下焙烧得到典型尺寸为1 5μm长、0 3℃m宽的正方形棒状二氧化钛。以直径为25 nm的纳米二氧化钛为原料，构建了方形棒状二氧化钛的骨架。EXAFS和XPS分析表明5-配位的存在。在乙醛的光氧化反应中，其光催化活性最高可达P25。这是由于二氧化钛颗粒中氧缺陷的高度分布所致，而二氧化钛颗粒是构成方形棒状骨架的组成部分。另外，氧缺陷通过捕获紫外光照射产生的空穴，有效地起到了光氧化作用。结果表明，氧缺陷和方棒形状对光氧化活性的产生是必不可少的。

Various TiO_2 were prepared by sol-gel process using titanium tetraisopropoxide (TTIP) and different dilos. We prepared successfully the highly ctystalline precursors, Ti (OCH (CH_3)CH_2CH_2O)_2 from 1, 3-butanediol and Ti (OCH_2CH_20)_2 from ethylene glycol. In particular, the titanium alkoxy-diolate from 1, 3-butanediol was drastically decomposed at 346℃ and transformed to TiO_2 phase with the square rod framework. The square rod TiO_2, whose typical size was estimated to be 1.5μm long and 0.3μm in width, was easily synthesized by the calcination of precursors at 500℃ in air. The framework of square rod TiO_2 was constructed from fine TiO_2 particles with 25 nm in diameter. EXAFS and XPS analyses revealed the presence of 5-coodinated. Ti species and oxygen defects.The photocatalytic activities as high as P25 was achieved during the photo-oxidation of acetaldehyde. The activity was due to the high distribution of oxygen defects of TiO_2 particles, which were components of the construction of the square rod framework. In addition, the oxygen defect acted effectively as a photo-oxidation site by the capture of hole generated by UV irradiation. It concluded that both oxygen defect and square rod shape were essential for the generation of the photo-oxidation activity