Photoinduced electron transfer in nanostructured assemblies of layered semiconducting oxide and methylviologen: Effect of the location of acceptor molecules
Photoinduced electron transfer in nanostructured assemblies of layered semiconducting oxide and methylviologen: Effect of the location of acceptor molecules
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DOI：
10.1016/j.micromeso.2009.04.011
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发表时间：
2009-07
影响因子：
5.2
通讯作者：
T. Nakato;Hitomi Edakubo;T. Shimomura
中科院分区：
文献类型：
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作者：
T. Nakato;Hitomi Edakubo;T. Shimomura
我们已经合成了层状hexaniobate，这是一种具有插层能力和光催化活性的半导体氧化物，和氧化还原活性的联吡啶物种（甲基紫精，MV 2+）的剥离-重堆叠和插层技术的纳米结构组件。通过使用三乙醇胺离子（TEAH+）作为剥离试剂的剥离物的分层和随后的剥离悬浮液的滴铸来制备剥离-再堆叠组件。紫外线照射引起的光诱导电子转移的mv 2+物质的mv 2+的mv 2+组件从mv 2+层产生甲基紫精自由基阳离子（MV+）。组装技术的差异产生了不同的MV+物种：剥离-重新堆叠组装的二聚体，但插层化合物的单体。XRD测量显示剥离-再堆叠组装体的无序层状结构，如宽衍射峰所证明的。这些观察结果表明，MV 2+离子并不严格纳入层间空间的氧化物，但目前在一个相对移动的环境与弱结合的氧化物层，这合理化的MV+阳离子的二聚化。另一方面，由尖锐的XRD峰证明的插层组装体的有序堆叠允许MV 2+阳离子固定在插层物的层间空间中。剥离-再堆叠组装体的无序环境归因于作为剥离试剂引入组装体的TEAH+离子的水合作用。
We have synthesized nanostructured assemblies of layered hexaniobate, which is a semiconducting oxide possessing intercalating capability and photocatalytic activity, and a redox-active bipyridinium species (methylviologen, MV2+) by exfoliation–restacking and intercalation techniques. The exfoliated–restacked assembly was prepared through delamination of the niobate using triethanolammonium ions (TEAH+) as an exfoliating reagent and subsequent drop-cast of the exfoliated suspension. UV-irradiation of the niobate–MV2+assemblies caused photoinduced electron transfer from the niobate layers to the MV2+species to produce methylviologen radical cations (MV+). The difference in the assembling technique yielded different MV+species: dimers for the exfoliated–restacked assembly but monomers for the intercalation compound. XRD measurements showed a disordered layered structure of the exfoliated–restacked assembly, as evidenced by broad diffraction peaks. These observations suggest that the MV2+ions are not strictly incorporated in the interlayer spaces of the niobate but present in a relatively mobile environment with weak binding to the oxide layers; this rationalizes the dimerization of the MV+cations. On the other hand, ordered stacking of the intercalated assembly evidenced by sharp XRD peaks allows immobilization of the MV2+cations in the interlayer spaces of the niobate. The disordered environment of the exfoliated–restacked assembly is ascribed to the hydration of the TEAH+ions introduced to the assembly as the exfoliating reagent.