A One-Step Mechanochemical Route to Core−Shell Ca2SnO4 Nanoparticles Followed by 119Sn MAS NMR and 119Sn Mössbauer Spectroscopy
A One-Step Mechanochemical Route to Core−Shell Ca2SnO4 Nanoparticles Followed by 119Sn MAS NMR and 119Sn Mössbauer Spectroscopy
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DOI：
10.1021/cm900590d
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发表时间：
2009-05
影响因子：
8.6
通讯作者：
V. Šepelák;K. Becker;I. Bergmann;Shigeru Suzuki;S. Indris;A. Feldhoff;P. Heitjans;C. Grey
中科院分区：
文献类型：
--
作者：
V. Šepelák;K. Becker;I. Bergmann;Shigeru Suzuki;S. Indris;A. Feldhoff;P. Heitjans;C. Grey
采用单步机械化学法制备了平均尺寸约为15 nm的锡酸钙（Ca2SnO4）纳米颗粒。高分辨率TEM研究揭示了机械合成的Ca2SnO4纳米颗粒的非均匀结构，由无序表面壳区包围的有序核心组成。Ca2SnO4纳米颗粒的内核具有完全有序的正交结构，表面壳层厚度约为1.5 nm。在纳米结构的机械合成锡酸盐中，表面壳区的体积分数约为50%。由于固态119Sn MAS NMR和119Sn穆斯堡尔谱能够探测Sn原子核的局部环境，因此对机械合成的Ca2SnO4的局部结构紊乱有价值的补充见解。结果表明，锡酸盐纳米颗粒的近表层是无序的，这是由于纳米颗粒的几何结构广泛扭曲所致。
Calcium stannate (Ca2SnO4) nanoparticles with an average size of about 15 nm were synthesized via single-step mechanochemical processing of binary oxide precursors at room temperature. High-resolution TEM studies revealed a nonuniform structure of mechanosynthesized Ca2SnO4 nanoparticles consisting of an ordered core surrounded by a disordered surface shell region. The inner core of a Ca2SnO4 nanoparticle possesses a fully ordered orthorhombic structure, and the surface shell exhibits the thickness of about 1.5 nm. The volume fraction of surface shell regions in the nanostructured mechanosynthesized stannate is estimated to be about 50%. Because of the ability of both solid-state 119Sn MAS NMR and 119Sn Mossbauer spectroscopies to probe the local environment of Sn nuclei, valuable complementary insight into the local structural disorder in mechanosynthesized Ca2SnO4 was obtained. It was concluded that the near-surface layers of stannate nanoparticles are disordered because of broadly distorted geometry of...