Hollow oxide formation by oxidation of Al and Cu nanoparticles
Hollow oxide formation by oxidation of Al and Cu nanoparticles
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DOI：
10.1063/1.2711383
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发表时间：
2007-04-01
影响因子：
3.2
通讯作者：
Mori, H.
中科院分区：
文献类型：
--
作者：
Nakamura, R.;Tokozakura, D.;Mori, H.
中空金属氧化物纳米粒子的形成，通过氧化过程中在低温下从295至423 K已被研究的Cu，Al，和Pb的透射电子显微镜。对于Cu和Al，由于在氧化过程中的空位聚集而获得中空的氧化物纳米颗粒，这是由于在氧化过程中金属离子通过氧化物层快速向外扩散而导致的。另一方面，Pb纳米颗粒变成固体PbO，因为PbO中的扩散系数差D-Pb < D-O不适合于空位簇的形成。较大尺寸的Cu和Al纳米颗粒在423 K下的氧化物生长行为总结如下：（i）对于Al，其表面快速形成的氧化物层在达到约1.5 nm的临界厚度后停止生长，（ii）Cu 2 O的生长继续，直到形成一定厚度的空心Cu 2 O。这表明在空心氧化物的形成中发生了两种不同的扩散过程：基于Cabrera-Mott理论的金属离子的快速向外扩散在空心Al氧化物的形成中起着重要的作用，而在Cu/Cu 2 O界面处的Kirkendall效应，其中Cu的扩散比氧气快得多，导致空心Cu 2 O的形成。(c)2007年，美国物理学会。
The formation of hollow metal oxide nanoparticles through the oxidation process at low temperatures from 295 to 423 K has been studied by transmission electron microscopy for Cu, Al, and Pb. For Cu and Al, hollow oxide nanoparticles are obtained as a result of vacancy aggregation in the oxidation processes, resulting from the rapid outward diffusion of metal ions through the oxide layer during the oxidation process. On the other hand, Pb nanoparticles turn to solid PbO because the diffusivity difference D-Pb < D-O in PbO does not lend itself to the formation of vacancy clusters. The oxide growth behavior of Cu and Al nanoparticles of a larger size at 423 K are summarized as follows: (i) for Al, the rapidly forming oxide layer on its surface stops growing once it reaches a critical thickness of about 1.5 nm, (ii) the growth of Cu2O continues until hollow Cu2O of a certain thickness is formed. This suggests the occurrence of two different diffusion processes in the formation of hollow oxides: the rapid outward diffusion of metal ions based on the Cabrera-Mott theory plays an important role in the formation of hollow Al-oxides, whereas the Kirkendall effect at the Cu/Cu2O interface, where Cu diffuses much faster than oxygen, brings about the formation of hollow Cu2O. (c) 2007 American Institute of Physics.