Nanomaterials Laboratory, Inorganic & Physical Chemistry Division, Indian institute of Chemical Technology, Hyderabad, Andhra Pradesh, India.
ACS Appl Mater Interfaces. 2012 Mar;4(3):1239-46. doi: 10.1021/am201354r. Epub 2012 Mar 8.
Here we demonstrate a facile method to synthesize high-surface-area TiO(2) nanoparticles in aqueous-ethanol system with tunable brookite/rutile and brookite/anatase ratio possessing high surface area that exhibits enhanced photoactivity. Titanium tetrachloride (TiCl(4)) is used as the metal precursor of choice and the tuning of phase compositions are achieved by varying the water:ethanol ratio, used as mixed solvent system. The synthesized samples were characterized in detail using X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), BET nitrogen sorption measurements, and UV-vis diffuse reflectance spectroscopy (UV-DRS). The photocatalytic activity of biphasic TiO(2) nanocrystals was evaluated by following the degradation kinetics of rhodamine-B dye in aqueous solution and under visible light. Mixed-phase TiO(2) nanostructures composing 83% brookite and 17% of rutile exhibited superior photoactivity when compared to Degussa P25 and phase-pure anatase nanocrystals. The exceptional photocatalytic activity of the synthesized nanostructures can be elucidated on the account of their large surface area and biphasic composition. On the basis of the detailed investigation reported herein, we conclude that tuning the ethanol volume in the mixed-solvent reaction system holds the key to tailor and control the final TiO(2) phase obtained.
在这里，我们展示了一种在水-乙醇体系中合成具有高比表面积的锐钛矿/金红石和锐钛矿/板钛矿可调比的高比表面积 TiO2 纳米粒子的简便方法，表现出增强的光催化活性。四氯化钛（TiCl4）用作首选的金属前体，通过改变用作混合溶剂体系的水：乙醇比来实现相组成的调谐。使用 X 射线衍射（XRD）、拉曼光谱、透射电子显微镜（TEM）、BET 氮气吸附测量和紫外可见漫反射光谱（UV-DRS）对合成的样品进行了详细的表征。通过跟踪罗丹明 B 染料在水溶液中的降解动力学和在可见光下的降解动力学，评估了双相 TiO2 纳米晶的光催化活性。与 Degussa P25 和单相锐钛矿纳米晶相比，由 83%锐钛矿和 17%金红石组成的混合相 TiO2 纳米结构表现出优异的光催化活性。所合成的纳米结构具有较大的比表面积和双相组成，可以解释其优异的光催化活性。基于本文的详细研究，我们得出结论，调整混合溶剂反应体系中的乙醇体积是控制最终 TiO2 相的关键。
