Transmission electron microscopy observation of oxide layer growth on Cu nanoparticles and formation process of hollow oxide particles
Transmission electron microscopy observation of oxide layer growth on Cu nanoparticles and formation process of hollow oxide particles
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DOI：
10.1557/jmr.2007.0362
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发表时间：
2007-10
影响因子：
2.7
通讯作者：
D. Tokozakura;R. Nakamura;Hideo Nakajima;J. Lee;Hirotaro Mori
中科院分区：
文献类型：
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作者：
D. Tokozakura;R. Nakamura;Hideo Nakajima;J. Lee;Hirotaro Mori
用透射电镜研究了323-373 K温度下Cu/Cu_2O纳米颗粒表面Cu_2O层的生长过程，探讨了Cu/Cu_2O界面上形成的空洞对氧化速率的影响。测量了初始粒径为10 ~ 35 nm的Cu纳米颗粒表面生成的Cu_2O的厚度随氧化时间的变化。在初始氧化阶段期间，直到氧化膜为约2.5nm厚，直径为10至35 nm的纳米颗粒上的氧化膜以几乎一致的速率快速生长。但在此之后，较小纳米颗粒的生长速率比较大纳米颗粒的生长速率急剧下降，这表明在Cu/Cu_2O界面附近形成的空洞阻止了Cu原子向外扩散，因为在相同的氧化时间下，较小纳米颗粒的空洞与内部Cu的体积比显著高于较大纳米颗粒。
The growth of a Cu_2O layer on Cu nanoparticles at 323–373 K was investigated by transmission electron microscopy to elucidate the influence of voids formed at the Cu/Cu_2O interface on the oxidation rate. The thickness of the Cu_2O formed on Cu nanoparticles with an initial diameter of 10 to ∼35 nm was measured as a function of oxidation time. During the initial oxidation stage until the oxide film is about 2.5 nm thick, the oxide film on nanoparticles of 10 to ∼35 nm in diameter grows rapidly at an almost consistent rate. After that, however, the growth rate of smaller nanoparticles decreases drastically compared with that of larger ones, suggesting that the voids formed near the Cu/Cu_2O interface prevent Cu atoms from diffusing outward, because the volume ratio of voids to inner Cu in the case of smaller nanoparticles is considerably higher than that for larger ones at the same oxidation time.