Size dependence of structural parameters in fcc and hcp Ru nanoparticles, revealed by Rietveld refinement analysis of high-energy X-ray diffraction data.
Size dependence of structural parameters in fcc and hcp Ru nanoparticles, revealed by Rietveld refinement analysis of high-energy X-ray diffraction data.
复制标题
DOI：
10.1038/srep31400
复制
发表时间：
2016-08-10
影响因子：
4.6
通讯作者：
Kitagawa H
中科院分区：
文献类型：
--
作者：
Song C;Sakata O;Kumara LS;Kohara S;Yang A;Kusada K;Kobayashi H;Kitagawa H
为了揭示钌纳米颗粒（Ru NPs）的CO氧化活性的起源，我们通过高能X射线衍射数据的Rietveld精修分析对Ru NPs进行了结构表征。对于六方密堆积（hcp）钌纳米颗粒，CO氧化活性降低域表面积。然而，对于面心立方（fcc）钌纳米颗粒，CO氧化活性变得更强，降低域表面积。在比较fcc Ru NPs与hcp Ru NPs时，我们发现，约2nm的hcp Ru NPs具有更小的畴表面积和更小的原子位移，比相同尺寸的fcc Ru NPs显示出更高的催化活性。相比之下，fcc Ru NPs大于3.5 nm，具有更大的域表面积，晶格畸变，和更大的原子位移，表现出更高的催化活性比hcp Ru NPs的相同大小。此外，对于2.2至5.4 nm的直径范围，fcc Ru NPs具有比hcp Ru NPs更大的原子位移。在fcc Ru纳米颗粒的CO氧化活性的增强可能是由于增加的缺陷，由于紧密堆积的平面和静态原子位移的晶格畸变。
To reveal the origin of the CO oxidation activity of Ruthenium nanoparticles (Ru NPs), we structurally characterized Ru NPs through Rietveld refinement analysis of high-energy X-ray diffraction data. For hexagonal close-packed (hcp) Ru NPs, the CO oxidation activity decreased with decreasing domain surface area. However, for face-centered cubic (fcc) Ru NPs, the CO oxidation activity became stronger with decreasing domain surface area. In comparing fcc Ru NPs with hcp Ru NPs, we found that the hcp Ru NPs of approximately 2 nm, which had a smaller domain surface area and smaller atomic displacement, showed a higher catalytic activity than that of fcc Ru NPs of the same size. In contrast, fcc Ru NPs larger than 3.5 nm, which had a larger domain surface area, lattice distortion, and larger atomic displacement, exhibited higher catalytic activity than that of hcp Ru NPs of the same size. In addition, the fcc Ru NPs had larger atomic displacements than hcp Ru NPs for diameters ranging from 2.2 to 5.4 nm. Enhancement of the CO oxidation activity in fcc Ru NPs may be caused by an increase in imperfections due to lattice distortions of close-packed planes and static atomic displacements.