Hydrothermal Reaction Mechanism and Pathway for the Formation of K2Ti6O13 Nanowires

Authors

  • Ting Zhang,

    1. Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Beijing, 100871, (P. R. China)
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  • Qing Chen,

    1. Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Beijing, 100871, (P. R. China)
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  • Lian-Mao Peng

    Corresponding author
    1. Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Beijing, 100871, (P. R. China)
    • Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Beijing, 100871, (P. R. China).
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  • This work was supported by the Ministry of Science and Technology (Grant Nos 2006CB932401 and 2006AA03Z350), and National Science Foundation of China (Grant Nos 10434010 and 90606026). The authors thank Dr. S. Zhang for valuable discussions.

Abstract

Calculations and detailed first principle and thermodynamic analyses have been performed to understand the formation mechanism of K2Ti6O13 nanowires (NWs) by a hydrothermal reaction between bulk Na2Ti3O7 crystals and a KOH solution. It is found that direct ion exchange between K+ and Na+ plus H+ interactions with [TiO6] octahedra in Na2Ti3O7 promote the formation of an intermediate H2K2Ti6O14 phase. The large lattice mismatch between this intermediate phase and the bulk Na2Ti3O7 structure, and the large energy reduction associated with the formation of this intermediate phase, drive the splitting of the bulk crystal into H2K2Ti6O14 NWs. However, these NWs are not stable because of large [TiO6] octahedra distortion and are subject to a dehydration process, which results in uniform K2Ti6O13 NWs with narrowly distributed diameters of around 10 nm.

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