Ultrathin films and hollow shells with pillared architectures fabricated via layer-by-layer self-assembly of titania nanosheets and aluminum Keggin ions
Ultrathin films and hollow shells with pillared architectures fabricated via layer-by-layer self-assembly of titania nanosheets and aluminum Keggin ions
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DOI：
10.1021/jp035818w
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发表时间：
2004-03
影响因子：
3.3
通讯作者：
Lianzhou Wang;Y. Ebina;K. Takada;T. Sasaki
中科院分区：
文献类型：
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作者：
Lianzhou Wang;Y. Ebina;K. Takada;T. Sasaki
通过静电自组装技术，在球形聚甲基丙烯酸甲酯（PMMA）模板和平面基底上逐层制备了具有柱撑结构的无机多层膜和空心壳。带正电的多氧阳离子的铝Keggin离子既作为无机粘合剂和作为柱撑剂在静电自组装剥离单层微晶的Ti0.9O2，产生新型的纳米薄膜和核-壳复合材料。紫外-可见吸收光谱表明，随着沉积周期的增加，吸收率逐渐增强，表明二氧化钛纳米片和铝多氧阳离子的多层组装体的规则生长。周期约为100 °的布拉格峰的演化。1.5纳米及其增强也支持形成纳米结构的多层膜和壳，容纳铝多氧杂合在纳米片画廊。深度X射线光电子能谱证实了它们的无机性质。在400 T下煅烧产生了TiO 2薄膜和空心壳，在TiO 2片之间有氧化铝柱。N-2吸附结果表明，柱撑空心球的高比表面积为260 m（2）g（-1）和纳米孔特征。
Inorganic multilayer films and hollow shells with pillared architectures have been fabricated layer-by-layer on spherical poly(methyl methacrylate) (PMMA) templates as well as flat substrates through the electrostatic self-assembly technique. Positively charged polyoxocations of aluminum Keggin ions were employed both as inorganic binder and as pillaring agent in electrostatic self-assembly with exfoliated unilamellar crystallites of Ti0.9O2, yielding new types of ultrathin films and core-shell composites. Ultraviolet-visible absorption spectra revealed progressive enhancement of absorbance with increasing deposition cycles, indicating the regular growth of multilayer assemblies of titania nanosheets and aluminum polyoxocations. Evolution of a Bragg peak with a periodicity of ca. 1.5 nm and its enhancement also supported the formation of nanostructured multilayer films and shells, accommodating aluminum polyoxocations in the nanosheet gallery. Depth X-ray photoelectron spectra confirmed their inorganic nature. Calcination at 400 T produced ultrathin films and hollow shells with alumina pillars between the titania sheets. N-2 adsorption results revealed a high specific surface area of 260 m(2) g(-1) and nanoporous feature for the pillared hollow spheres.