Indris Sylvio, Amade Roger, Heitjans Paul, Finger Mina, Haeger Andreas, Hesse Diethard, Grünert Wolfgang, Börger Alexander, Becker Klaus Dieter
Institut für Physikalische Chemie und Elektrochemie, Universität Hannover, Callinstrasse 3-3A, 30167 Hannover, Germany.
J Phys Chem B. 2005 Dec 15;109(49):23274-8. doi: 10.1021/jp054586t.
Titanium dioxide (TiO2) is widely used for applications in heterogeneous photocatalysis. We prepared nanocrystalline powders of the anatase as well as the rutile modification by high-energy ball milling of the coarse grained source materials for up to 4 h. The resulting average grain size was about 20 nm. The morphology of the powders was investigated with transmission electron microscopy, X-ray powder diffraction, and BET surface area determination. Measurements of the catalytic activity reveal a maximum as a function of the milling time at about 40 min. This maximum could be explained by a superposition of two counteracting effects. The first one is the increase of the specific surface area resulting in an increase of the catalytic activity, and the second one is a change of the electronic structure at the surface of the TiO2 particles corresponding to a reduction of the surface. The latter one was confirmed by light absorption experiments, X-ray photoelectron spectroscopy, and electron paramagnetic resonance spectroscopy.
二氧化钛（TiO₂）广泛应用于多相光催化领域。我们通过对粗晶粒原料进行长达4小时的高能球磨，制备了锐钛矿型以及金红石型改性的纳米晶粉末。所得平均晶粒尺寸约为20纳米。通过透射电子显微镜、X射线粉末衍射和BET比表面积测定对粉末的形态进行了研究。催化活性的测量结果显示，作为球磨时间的函数，在约40分钟时出现最大值。这个最大值可以用两种相互抵消的效应叠加来解释。第一种效应是比表面积的增加导致催化活性提高，第二种效应是TiO₂颗粒表面电子结构的变化，这对应于表面的还原。后一种效应通过光吸收实验、X射线光电子能谱和电子顺磁共振光谱得到了证实。
