Template-free synthesis of novel, highly-ordered 3D hierarchical Nb3O7(OH) superstructures with semiconductive and photoactive properties
Template-free synthesis of novel, highly-ordered 3D hierarchical Nb3O7(OH) superstructures with semiconductive and photoactive properties
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DOI：
10.1039/c4ta02202e
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发表时间：
2014-08-14
影响因子：
11.9
通讯作者：
Scheu, Christina
中科院分区：
文献类型：
--
作者：
Betzler, Sophia B.;Wisnet, Andreas;Scheu, Christina
三维有序Nb3O7(OH)介晶可以由纳米级的积木块自组织而成。本研究的重点是介晶的合成和详细研究，这可以通过一步无模板剂的水热合成方法来实现。得到的立方体超结构由周期性的纳米线网络组成，具有大的比表面积、高的结晶度、3.2 eV的带隙和光催化活性。它们的易加工性与著名的优异性能相结合，使其成为大量应用的有前途的候选材料。这包括光化学和光物理器件，其中Nb_3O_7(OH)介晶可以用作电极材料，因为它们是半导体性的，并且具有很大的表面积。一般来说，介晶自组织形成过程中所涉及的作用力还没有被完全理解。在这方面，利用透射电子显微镜、扫描电子显微镜对Nb_3O_7(OH)介晶的组装进行了深入的研究。UV/Vis测量和电子能量损失光谱。在此基础上提出了一种形成机制，扩展了文献报道的介晶形成机制的数量。此外，我们的研究揭示了不同类型的纳米线结，并研究了它们在网络稳定中的作用。
3D hierarchical Nb3O7(OH) mesocrystals can be formed by self-organization from nanometer sized building blocks. The present study focuses on the synthesis and detailed investigation of mesocrystals, which can be achieved from a one-step, template-free hydrothermal synthesis approach. The obtained cubic superstructures consist of a periodic nanowire-network and combine a large surface area, high crystallinity, with a band gap of 3.2 eV and photocatalytic activity. Their easy processability in combination with the named excellent properties makes them promising candidates for a large number of applications. These include photochemical and photophysical devices where the Nb3O7(OH) mesocrystals can be used as electrode material since they are semiconducting and possess a large surface area. Generally the forces involved in the self-organized formation of mesocrystals are not fully understood. In this regard, the assembly of the Nb3O7(OH) mesocrystals was investigated in-depth applying transmission electron microscopy, scanning electron microscopy. UV/Vis measurements and electron energy-loss spectroscopy. Based on the achieved results a formation mechanisms is proposed, which expands the number of mechanisms for mesocrystal formation reported in literature. In addition, our study reveals different types of nanowire junctions and investigates their role at the stabilization of the networks.