Templated synthesis of shape-controlled, ordered TiO2 cage structures.
Templated synthesis of shape-controlled, ordered TiO2 cage structures.
复制标题
DOI：
10.1002/smll.201100579
复制
发表时间：
2011-07
期刊：
影响因子：
13.3
通讯作者：
Yonghui Deng;H. Tüysüz;Joel Henzie;P. Yang
中科院分区：
文献类型：
--
作者：
Yonghui Deng;H. Tüysüz;Joel Henzie;P. Yang
银纳米颗粒周期性有序的复合材料可以被合理地设计成具有跨越纳米和微米长度尺度的特征。[ 1-4 ]因此，在产生具有优异结晶度、高表面积和可控孔系统的热稳定金属氧化物结构以用于多相催化、燃料电池开发、太阳能转换、光子学和气体传感方面已经取得了很大进展。[ 5-10 ]在该过程中，所需特征的尺寸取决于模板的尺寸-包括表面活性剂和嵌段共聚物的分子种类充当纳米级孔的模板，[ 11，12 ]而胶体颗粒模板结构具有纳米至微米尺寸范围的孔。[ 13-18 ]在这些模板工艺中，胶体晶体模板由于新的组装技术能够实现更大的周期性而受到更多的关注。在典型的方法中，均匀尺寸的胶体颗粒（二氧化硅球、聚合物球或单分散纳米晶体）组装成2D或3D阵列。在形成晶格之后，颗粒之间的空间填充有含有所需材料组成的前体的溶液。通过干燥和退火样品将该前体沉积到模板上。最后，原始模板被选择性地蚀刻掉，以留下在胶体模板的界面处形成的固体晶体骨架。[ 19 ]还报道了通过使用二氧化硅纳米颗粒-聚合物多层的静电逐层自组装，然后除去聚苯乙烯胶乳模板，通过胶体模板路线制造单层中空无机二氧化硅和无机混合球。[ 20 ]类似的溶液模板方法已经产生了包括ZrO 2的不同材料成分的相关笼状结构。或者，可以使用与化学气相沉积（CVD）或原子层沉积（ALD）相结合的现有气相反应方法来获得更多样化的材料成分范围。在典型的CVD或ALD工艺中，组装的晶格暴露于一种或多种挥发性前体，然后挥发性前体在衬底表面上分解以产生期望的材料。[ 33 ]对结构的组成和壳厚度的精确控制是这些方法相对于溶液模板法的最大优点。例如，Zhang等人在CVD方法中使用SBA-15作为硬模板和乙烯气体来制备有序的中孔碳。[ 34 ] Huang等人报道了一项有趣的研究。在蝴蝶翅膀的纳米结构表面上使用ALD来模板Al…
Silver Nanoparticles Periodically ordered composite materials can be rationally engineered with features spanning nanometer and micro-meter length scales. [ 1–4 ] As a result, much progress has been made in generating thermally stable metal oxide structures with excellent crystallinity, high surface area, and controllable pore systems for applications in heterogeneous catalysis, fuel cell development, solar energy conversation, photonics, and gas-sensing. [ 5–10 ] In this process, the size of the desired features depends on the dimensions of the templates—molec-ular species including surfactants and block copolymers act as templates for nanoscale pores, [ 11 , 12 ] while colloidal particles template structures with pores in the nano-to microscale size regime. [ 13–18 ] Among these templating processes, col-loidal crystal templates have gained more attention as new assembly techniques enable larger periodicities. In a typical method, uniformly sized colloidal particles (silica spheres, polymer spheres, or monodisperse nanocrystals) are assembled into 2D or 3D arrays. After formation of the lattice, the space between the particles is fi lled with a solution containing the precursor of the desired material composition. This precursor is deposited onto the template by drying and annealing the sample. Finally, the original template is selectively etched away to leave a solid crystalline skeleton formed at the interfaces of the colloidal template. [ 19 ] Fabrication of monolayer hollow inorganic silica and inorganic hybrid spheres is also reported through the colloid templating route by using elec-trostatic layer-by-layer self-assembly of silica nanoparticle– polymer multilayers, followed by removal of the polystyrene latex template. [ 20 ] Similar solution-templating approaches have generated related cage structures of different material compositions including ZrO 2 , Alternatively, a more diverse range of material compositions can be accessed using existing gas-phase reaction methods combined with chemical vapor deposition (CVD) or atomic layer deposition (ALD). In a typical CVD or ALD processes, the assembled lattice is exposed to one or more volatile precursors, which then decompose on the sub-strate surface to produce the desired material. [ 33 ] Precise control of the composition and shell thickness of the structure are the biggest advantages of these methods over the solution-templating approach. For example, Zhang et al. used SBA-15 as a hard template and ethylene gas in a CVD approach to prepare ordered mesoporous carbon. [ 34 ] And an interesting study was reported by Huang et al. using ALD on the nanostructured surfaces of butterfl y wings to template Al …