STEM study of bimetallic Pd-Ru nanoparticles
STEM study of bimetallic Pd-Ru nanoparticles
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双金属 Pd-Ru 纳米颗粒的 STEM 研究
DOI：
10.1093/jmicro/dfv245
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发表时间：
2015
期刊：
影响因子：
1.8
通讯作者：
S. Matsumura
中科院分区：
文献类型：
--
作者：
T. Yamamoto;K. Kusada;K. Sato;S. Yoshioka;H. Kobayashi;K. Nagaoka;H. Kitagawa;S. Matsumura
双金属合金纳米颗粒（NP）因其可能具有协同效应而被广泛研究，具有广泛的应用前景[1]。尽管Pd-Ru体系是不混溶合金体系，但过饱和固溶体Pd1-xRux NPs的合成最近已成功[2]。过饱和固溶体Pd1-xRux NPs对CO选择性氧化和NOx还原表现出优异的催化性能。纳米粒子的催化性能取决于其电子结构、尺寸、组成、表面结构等。在本研究中，使用像差校正透射电子显微镜在原子尺度上研究了 NOx 还原反应前后 Pd1-xRux NP 的结构。 Pd1-xRux 合金纳米粒子是通过在聚乙烯吡咯烷酮 (PVP) 存在下在沸腾的乙二醇 (EG) 溶液中还原 RuCl3 和 K2PdCl4 来制备的。合成的 Pd1-xRux NPs 负载在 γ-Al2O3 上。 Pd1-xRux NP 的 STEM 观察和 STEM-EDX 化学分布分析由配备双 SDD 探测器的 JEOL JEMARM 200F 进行。观察到不同组成的 Pd1-xRux NP 的形状差异。富钯纳米粒子的主要形状是二十面体和球形，具有面心立方晶体结构。增加 Pd1-xRux 纳米颗粒中的 Ru 含量，纳米颗粒表面更加粗糙，因为单个纳米颗粒由几个具有 fcc 和 hcp 晶体结构的小颗粒组成。各个合成纳米粒子中的 Pd 和 Ru 元素几乎均匀分布。在高达 600 ℃ 的 NOx 还原催化反应后，Pd1-xRux NPs 被烧结并分离成两相，具有富含 Pd 的 fcc 和富含 Ru 的 hcp 晶体结构。 [1] OG Ellert 等人，Russ。化学。修订版 83 (2014) 718-732.[2] K. Kusada 等人，J. Am。化学。苏克。 136（2014）1864-1871。
Bimetallic alloy nanoparticles (NPs) have been extensively investigated for a wide range of applications because they may have synergetic effects [1]. Synthesis of supersaturated solid solution Pd1-xRux NPs have succeeded recently [2] although Pd-Ru system is immiscible alloy system. The supersaturated solid solution Pd1-xRux NPs exhibit superior catalytic property for CO selective oxidation and NOx reduction. The catalytic properties of the NPs depend on their electronic structure, size, composition, surface structure and so on. In this study, the structure of the Pd1-xRux NPs before and after NOx reduction reaction were investigated in atomic scale using an aberration-corrected transmission electron microscopey. Pd1-xRux alloy NPs were prepared by reduction of RuCl3 and K2PdCl4 in a boiling ethylene glycol (EG) solution in the presence of polyvinyl-pyrrolidone (PVP). The synthesized Pd1-xRux NPs were supported on γ-Al2O3. STEM observations and STEM-EDX chemical distribution analyses of Pd1-xRux NPs were performed by JEOL JEMARM 200F with double SDD detectors. The shape difference were observed for of Pd1-xRux NPs with different compositions. The major shapes for Pd-rich NPs were icosahedral and spherical with fcc crystal structure. Increasing the Ru content in Pd1-xRux NPs, the nanoparticle surfaces were more rugged because the individual NPs consist of several small grains with fcc and hcp crystal structures. Pd and Ru elements in the individual as-synthesized NPs were distributed almost uniformly. After the catalytic reaction of NOx reduction up to 600 ºC, the Pd1-xRux NPs were sintered and separated to two phases with Pd-rich fcc and Ru-rich hcp crystal structures.[1] OG Ellert et al., Russ. Chem. Rev. 83 (2014) 718-732.[2] K. Kusada et al., J. Am. Chem. Soc. 136 (2014) 1864-1871.