Inorganic Chemistry III - Materials Synthesis and Characterization, Ruhr-Universität Bochum, D-44780 Bochum, Germany.
Nanoscale. 2013 Sep 7;5(17):8045-55. doi: 10.1039/c3nr00824j.
The phase selective synthesis of nanocrystalline TiO2, titania, in ionic liquids (ILs) is explored. The influence not only of the IL but also of the Ti-precursor, pH, and temperature is investigated. Sonochemical synthesis, microwave synthesis and conventional heating are compared. In the case of Ti(O(i)Pr)4 (O(i)Pr = isopropyl) as the Ti-source the ILs [C4mim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide), [C3mimOH][Tf2N] (1-(3-hydroxypropyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)amide), [C4Py][Tf2N] (butylpyridinium bis(trifluoromethanesulfonyl)amide), [N1888][Tf2N] (methyltrioctylammonium bis(trifluoromethanesulfonyl)amide), and [P66614][Tf2N] (tetradecyltrihexyl phosphonium bis(trifluoromethanesulfonyl)amide) led at ambient temperature to TiO2 in the form of anatase. The morphology of nano-anatase is controlled by the IL cation. Anatase nanospheres with a crystal size below 10 nm are obtained in [C3mimOH][Tf2N], [P66614][Tf2N] and [C4Py][Tf2N], whilst nanorods with a length and diameter of ∼10 to 20 and 5 nm are formed in [N1888][Tf2N] and spindle-shaped particles with an average length of 10-25 nm are formed in [C4mim][Tf2N]. Calcination at temperatures above 730 °C leads to rutile. When using TiCl4 as the Ti-precursor an anatase-rutile mixture forms under ambient conditions. Pure rutile can be obtained under ambient conditions in the presence of an appropriate volume of aqueous HCl. At moderate to high pH values pure anatase can be obtained even from TiCl4. The photocatalytic activity of the obtained TiO2 materials has been assessed by the photodegradation of an aqueous methyl orange solution under UV light. The results indicate that the photocatalytic activity of anatase-brookite mixtures obtained in [C4mim][Tf2N], [N1888][Tf2N] and [P66614][Tf2N] is higher than that of pure anatase which is formed in [C3mimOH][Tf2N] and [C4Py][Tf2N] and competitive with commercially available catalysts.
探索了在离子液体（ILs）中选择性合成纳米晶 TiO2（二氧化钛）。不仅考察了 IL 的影响，还考察了 Ti 前体、pH 值和温度的影响。比较了超声化学合成、微波合成和常规加热。在 Ti(O(i)Pr)4（O(i)Pr = 异丙基）作为 Ti 源的情况下，ILs [C4mim][Tf2N]（1-丁基-3-甲基咪唑双（三氟甲磺酰基）酰胺）、[C3mimOH][Tf2N]（1-(3-羟丙基）-3-甲基咪唑双（三氟甲磺酰基）酰胺）、[C4Py][Tf2N]（丁基吡啶双（三氟甲磺酰基）酰胺）、[N1888][Tf2N]（甲基三辛基氯化铵双（三氟甲磺酰基）酰胺）和 [P66614][Tf2N]（十四烷基三己基膦双（三氟甲磺酰基）酰胺）在环境温度下生成锐钛矿形式的 TiO2。纳米锐钛矿的形态由 IL 阳离子控制。在 [C3mimOH][Tf2N]、[P66614][Tf2N] 和 [C4Py][Tf2N]中获得了晶体尺寸低于 10nm 的锐钛矿纳米球，而在 [N1888][Tf2N]中形成了长度和直径约为 10-20 和 5nm 的纳米棒，在 [C4mim][Tf2N]中形成了平均长度为 10-25nm 的纺锤形颗粒。在 730°C 以上的温度下煅烧会导致金红石形成。当使用 TiCl4 作为 Ti 前体时，在环境条件下形成锐钛矿-金红石混合物。在存在适量水合 HCl 的情况下，即使在环境条件下也可以获得纯金红石。即使使用 TiCl4，在中等至高 pH 值下也可以获得纯锐钛矿。通过在紫外光下光降解水溶液甲基橙评估了所获得的 TiO2 材料的光催化活性。结果表明，在 [C4mim][Tf2N]、[N1888][Tf2N] 和 [P66614][Tf2N]中获得的锐钛矿-板钛矿混合物的光催化活性高于在 [C3mimOH][Tf2N]和 [C4Py][Tf2N]中形成的纯锐钛矿，与市售催化剂相当。
