Photoelectrochemical oxidation of methanol on oxide nanosheets.
Photoelectrochemical oxidation of methanol on oxide nanosheets.
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DOI：
10.1021/jp056210l
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发表时间：
2006-02
期刊：
影响因子：
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通讯作者：
K. Izawa;Takashi Yamada;U. Unal;S. Ida;Ozge Altuntasoglu;M. Koinuma;Y. Matsumoto
中科院分区：
文献类型：
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作者：
K. Izawa;Takashi Yamada;U. Unal;S. Ida;Ozge Altuntasoglu;M. Koinuma;Y. Matsumoto
研究了乙醇在Nb6O17、Ca2Nb3O10、Ti(0.91)O2、Ti4O9、MnO2等不同纳米片电极上的光电化学氧化性能，评价了乙醇作为牺牲剂对水的光催化作用。利用静电原理，采用逐层(LBL)法制备了纳米片电极。在甲醇溶液中，Nb6O17和Ca2Nb3O10纳米片的光氧化电流密度最高，而Ti(0.91)O2、Ti4O9和MnO2纳米片的光氧化电流密度依次较低。光电流密度的大小与光催化活性的大小一致，说明醇的光氧化程度决定了醇在水光解过程中的活性。光电流与电极上纳米片层的数量无关，这表明只有直接附着在衬底上的单纳米片层才起到光电催化剂的作用，层间空间并不重要。因此，Nb_6O_(17)单纳米片层上较高的光氧化电流意味着在光照下电子和空穴的电荷分离很大，并且与Nb_6O_(17)纳米片层上的表面复合相比，CH3OH捕获空穴的过程非常快。过渡金属阳离子在纳米片上的吸附起到了表面复合中心的作用，因为吸附后光电流减小。从各种光电化学行为的角度对其光催化机理进行了详细的讨论。
Photoelectrochemical oxidation of alcohol on various nanosheet electrodes such as Nb6O17, Ca2Nb3O10, Ti(0.91)O2, Ti4O9, and MnO2 system host layers were measured to evaluate the photocatalysis of water photolysis with alcohol as a sacrificial agent. The nanosheet electrodes were prepared by the layer-by-layer (LBL) method, using electrostatic principles. The highest photooxidation current density was observed in methanol solution for Nb6O17 and Ca2Nb3O10 nanosheets, while the density was lower for Ti(0.91)O2, Ti4O9, and MnO2 nanosheets in decreasing order. The rank in the photocurrent density was in agreement with that in the photocatalytic activity, which means that the degree of photooxidation of the alcohol determines the activity of the alcohol in the water photolysis process. The photocurrent was independent of the number of nanosheet layers on the electrode, indicating that only the mono-nanosheet layer attached directly on a substrate acts as a photoelectrocatalyst and that the interlayer space is not important. Consequently, higher photooxidation current on the Nb6O17 mono-nanosheet layer means that the charge separation of electron and hole under illumination is very large and that the hole-capturing process by CH3OH is very quick compared with the surface recombination on the Nb6O17 nanosheet. The adsorption of a transition metal cation on the nanosheet acted as the surface recombination center, because the photocurrent decreased after the adsorption. The photocatalytic mechanism has been discussed in detail in terms of various photoelectrochemical behaviors.