How Phase Composition Influences Optoelectronic and Photocatalytic Properties of TiO2
How Phase Composition Influences Optoelectronic and Photocatalytic Properties of TiO2
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DOI：
10.1021/jp110190a
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发表时间：
2011-02-10
影响因子：
3.7
通讯作者：
Mul, Guido
中科院分区：
文献类型：
--
作者：
Carneiro, Joana T.;Savenije, Tom J.;Mul, Guido
在本研究中，通过在500~900℃的温度范围内焙烧，改变了溶胶-凝胶法合成的二氧化钛中金红石和锐钛矿相的比例，并通过时间分辨微波电导测量(TRMC)分析了其光电性质的变化，并通过比较其光催化活性来评价其光催化性能。金红石的存在通过捕获金红石表面的正电荷来提高电荷分离效率，这是由于金红石表面的电导率水平和电子寿命的增加而产生的。这些现象导致当与锐钛矿型表面接触时，锐钛矿型表面的有效空穴浓度降低，锐钛矿型表面是具有最高本征反应活性的表面。金红石。事实上，金红石的存在导致了对亚甲基蓝和环己烷选择性光催化氧化的降解性能较差。金红石的存在的负面影响可以通过改善锐钛矿相的形态特性来补偿，例如P25中存在的那些。提出并讨论了一种新的构效关系。
In the present study the ratio of rutile and anatase phases in sol-gel-synthesized TiO2 was varied by calcination at temperatures ranging from 500 to 900 degrees C. Changes in opto-electronic properties were analyzed by time-resolved microwave conductance measurements (TRMC) and evaluated by comparison of the photocatalytic activity. The presence of rutile improves the charge separation efficiency by trapping of positive charges at the rutile surface, as derived from the increased levels of conductivity and electron lifetimes. These phenomena result in a decrease in the effective hole concentration at the anatase surface, the TiO2 surface with the highest intrinsic reactivity, when in contact with. rutile. Indeed, the presence of rutile results in inferior performance in the degradation of methylene blue and cyclohexane-selective photocatalytic oxidation. The negative effect of the presence of rutile can be compensated by improved morphological properties of the anatase phase, such as those present in P25. A novel structure-activity relationship is proposed and discussed.