Synergism between rutile and anatase TiO2 particles in photocatalytic oxidation of naphthalene
Synergism between rutile and anatase TiO2 particles in photocatalytic oxidation of naphthalene
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DOI：
10.1016/s0926-860x(02)00610-5
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发表时间：
2003-05-15
影响因子：
5.5
通讯作者：
Matsumura, M
中科院分区：
文献类型：
--
作者：
Ohno, T;Tokieda, K;Matsumura, M
以不同种类的二氧化钛（TiO 2）粉体为光催化剂，以分子氧为电子受体，研究了乙腈-水混合溶液中萘的光催化氧化。萘的主要产物是2-甲酰基肉桂醛。对于该反应，通常用作光催化剂的非常小的TiO 2颗粒是无活性的，这可能是因为带弯曲对于萘的氧化是必要的。如果颗粒不是非常小，则纯金红石和纯金红石粉末显示相当高的活性，并且那些同时含有金红石和金红石相的粉末显示最高的活性。当通过热处理将纯的金红石粉末部分（约90%）转化为金红石形式时，活性大大提高。纯金红石颗粒的活性也通过将它们与少量的小尺寸的金红石颗粒物理混合而增强，所述金红石颗粒对于该反应是惰性的。这些结果可以用金红石和金红石颗粒之间的协同作用来解释。我们认为电子从金红石颗粒转移到金红石颗粒，即萘在金红石颗粒上主要被氧化，氧在金红石颗粒上主要被还原。该电子转移过程由用于还原氧的TiO 2电极的电化学性质支持。(C)2002 Elsevier Science B. V.保留所有权利。
Photocatalytic oxidation of naphthalene was investigated in a mixed solution of acetonitrile and water using various kinds of titanium dioxide (TiO2) powders as the photocatalysts and molecular oxygen as the electron acceptor. The main product from naphthalene is 2-formylcinnamaldehyde. For this reaction, anatase small TiO2 particles, which are commonly used as photocatalyst, are inactive, probably because band bending is necessary for the oxidation of naphthalene. If the particles are not extremely small, pure rutile and pure anatase powders show fairly high activity, and those containing both anatase and rutile phases show the highest activity. When a pure anatase powder is partly (about 90%) converted to the rutile form by heat treatment, the activity is largely enhanced. The activity of pure rutile particles is also enhanced by physically mixing them with a small amount of small-sized anatase particles, which are inactive for this reaction. These results can be explained by the synergism between rutile and anatase particles. We consider that electrons are transferred from rutile particles to anatase particles, i.e. naphthalene is mainly oxidized on rutile particles and oxygen is mainly reduced on anatase particles. This electron transfer process is supported by electrochemical properties of TiO2 electrodes for reduction of oxygen. (C) 2002 Elsevier Science B.V. All rights reserved.