Institute of Technical Chemistry, Photocatalysis and Nanotechnology Research Unit, Leibniz Universität Hannover, Callinstr.3, 30167 Hannover, Germany.
Photochem Photobiol Sci. 2013 Apr;12(4):602-9. doi: 10.1039/c2pp25217a.
Titanium dioxide nanoparticles consisting of pure anatase, anatase-rich, brookite-rich, and pure brookite modifications were synthesized and characterized by X-ray diffraction, field emission-scanning electron microscopy and nitrogen adsorption. The phase transformations among the three modifications of TiO2 (anatase, brookite, and rutile) and the photocatalytic activities of these nanoparticles were investigated by heat treatment over the temperature range from 400 to 800 °C and by the photooxidation of methanol, respectively. Direct transformation of anatase and brookite to rutile was observed, while in the case of the anatase-brookite mixture, anatase transforms firstly to brookite and then to rutile. The photocatalytic activity measurements indicate that brookite nanoparticles exhibit higher photocatalytic activities than anatase, and a comparable activity to that of the anatase-rich nanoparticles. The phase transformations and photocatalytic results are discussed regarding their dependence on crystallite size, surface area, and phase composition.
合成了由纯锐钛矿、锐钛矿富、板钛矿富和纯板钛矿修饰的二氧化钛纳米粒子，并通过 X 射线衍射、场发射扫描电子显微镜和氮气吸附对其进行了表征。通过在 400 至 800°C 的温度范围内进行热处理和通过光氧化甲醇分别研究了 TiO2（锐钛矿、板钛矿和金红石）的三种修饰形式之间的相变和这些纳米粒子的光催化活性。观察到锐钛矿和板钛矿直接转化为金红石，而在锐钛矿-板钛矿混合物的情况下，锐钛矿首先转化为板钛矿，然后转化为金红石。光催化活性测量表明，板钛矿纳米粒子表现出比锐钛矿更高的光催化活性，并且与富锐钛矿纳米粒子的活性相当。讨论了相变和光催化结果，以探讨其对晶粒尺寸、表面积和相组成的依赖性。
