Formation mechanism of H2Ti3O7 nanotubes -: art. no. 256103
Formation mechanism of H2Ti3O7 nanotubes -: art. no. 256103
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DOI：
10.1103/physrevlett.91.256103
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发表时间：
2003-12-19
影响因子：
8.6
通讯作者：
Zhou, WZ
中科院分区：
文献类型：
--
作者：
Zhang, S;Peng, LM;Zhou, WZ
通过对不同反应时间的系列样品的透射电子显微镜观察和大量的从头计算，研究了晶态二氧化钛和氢氧化钠一步反应生成H_2Ti3O_7纳米管的机理。研究发现，这种生长机制包括几个步骤。结晶的二氧化钛与氢氧化钠反应，形成高度无序的相，再结晶成一些H_2Ti3O_7薄片。顶表面的H缺陷导致了表面Ti3O72-层的不对称环境。表面张力、弹性应变能、层间耦合能和库仑力的计算表明，非对称环境是单片H_2Ti3O_7从平板上解离并形成多壁螺旋纳米管的主要驱动力。
Formation mechanism of H2Ti3O7 nanotubes by single-step reaction of crystalline TiO2 and NaOH has been investigated via transmission electron microscopy examinations of series specimens with different reaction times and extensive ab initio calculations. It was found that the growth mechanism includes several steps. Crystalline TiO2 reacts with NaOH, forming a highly disordered phase, which recrystallized into some H2Ti3O7 thin plates. H-deficiency on the top surface leads to an asymmetrical environment for the surface Ti3O72- layer. The calculations of the surface tension, elastic strain energy, interlayer coupling energy, and Coulomb force indicated that the asymmetrical environment is the principal driving force of the cleavage of the single sheets of H2Ti3O7 from the plates and the formation of the multiwall spiral nanotubes.