The mechanism for hydrothermal growth of zinc oxide
The mechanism for hydrothermal growth of zinc oxide
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DOI：
10.1039/c1ce06039b
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发表时间：
2012-01-01
期刊：
影响因子：
3.1
通讯作者：
Ducker, William A.
中科院分区：
文献类型：
--
作者：
Nicholas, Nathan Johann;Franks, George V.;Ducker, William A.
研究了在pH值接近11的氢氧化铵溶液（0.3 M NH 4 OH）中ZnO的水热生长机理。使用傅里叶变换红外光谱（FTIR）、X射线光子光谱（XPS）、X射线衍射（XRD）和二次离子质谱（西姆斯）表征在20-90 ℃和环境压力下形成的产物。在这些条件下，ZnO的生长经由ε-Zn（OH）（2）（纤锌矿）的初始沉淀发生，其随后脱水以形成纤锌矿ZnO。同位素示踪实验表明，大多数的氧原子不与水混合的转化过程中从纤锌矿ZnO，因此，反应进行主要是在固相，而不是通过溶解，然后再沉淀。XPS结果表明，在较低的温度下，水热ZnO的表面主要由氢氧化锌组成，并且在较高的温度下，有一个显着的氢氧化锌馏分持久。总之，这些结果表明，大部分固溶体界面主要由氢氧化锌而不是ZnO组成。这些发现可能对理解如何使用小有机分子来控制在水热条件下生长的氧化锌晶体的形态具有影响。
The mechanism for hydrothermal growth of ZnO was studied in ammonium hydroxide solution at pH near 11 (0.3 M NH4OH). The products formed at 20-90 degrees C and ambient pressure were characterised using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photon Spectroscopy (XPS), X-ray Diffraction (XRD) and Secondary Ion Mass Spectroscopy (SIMS). Under these conditions, the growth of ZnO occurs via the initial precipitation of epsilon-Zn(OH)(2) (Wulfingite), which subsequently dehydrates, to form Wurtzite ZnO. Isotope tracking experiments show that most of the oxygen atoms do not mix with water during the conversion from Wulfingite to ZnO, and thus that the reaction proceeds primarily in the solid phase rather than through dissolution then reprecipitation. XPS results show that the surface of hydrothermal ZnO consists primarily of zinc hydroxide at lower temperatures, and there is a significant fraction of zinc hydroxide persisting at higher temperatures. Together these results show that much of the solid-solution interface is mainly comprised of zinc hydroxide not ZnO. These findings may have implications for understanding how small organic molecules can be used to control the morphology of zinc oxide crystals grown under hydrothermal conditions.