Gold Nanowire Networks: Synthesis, Characterization, and Catalytic Activity
Gold Nanowire Networks: Synthesis, Characterization, and Catalytic Activity
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DOI：
10.1021/la104092b
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发表时间：
2011-04-05
期刊：
影响因子：
3.9
通讯作者：
Silva, Fernando
中科院分区：
文献类型：
--
作者：
Chirea, Mariana;Freitas, Andreia;Silva, Fernando
平均宽度为 17.74 nm (AuNWN1) 或 23.54 nm (AuNWN2) 的金纳米线网络 (AuNWN) 是通过在 40 摄氏度的低共熔溶剂（例如乙醇或 reline）中用硼氢化钠粉末直接还原 HAuCl4 来合成的。它们的宽度和长度取决于溶剂类型和 NaBH4/HAuCl4 摩尔比（32在乙醇中和 5.2 在 reline 中）。金纳米线网络的高分辨率透射电子显微镜 (HR-TEM) 分析显示，d = 2.36、2.04、1.44 和 1.23 埃的多晶纳米粉末具有清晰的晶格边缘，对应于面心立方金的 (111)、(200)、(220) 或 (311) 晶面。纯化的 AuNWN 用作催化剂，用硼氢化钠在水溶液中将对硝基苯胺化学还原为二氨基亚苯基。通过紫外-可见光谱实时监测反应。结果表明，在存在由来自 reline 的尿素稳定的金纳米线网络 (AuNWN2) 的情况下，还原过程比存在由来自乙醇的乙二醇稳定的金纳米线网络 (AuNWN1) 的情况下快六倍。这是因为在 reline 中合成的金纳米线上的角和边缘数量比在 ethaline 中合成的金纳米线上的角和边缘的数量要多，这由两种类型的金纳米线网络记录的 X 射线衍射 (XRD) 图案证明。然而，两种类型的纳米材料都决定了反应时间短和对硝基苯胺向二氨基亚苯基的高转化率。这些金纳米材料代表了新一代催化剂的新成员：金基催化剂。
Gold nanowire networks (AuNWNs) with average widths of 17.74 nm (AuNWN1) or 23.54 nm (AuNWN2) were synthesized by direct reduction of HAuCl4 with sodium borohydride powder in deep eutectic solvents, such as ethaline or reline, at 40 degrees C. Their width and length were dependent on the type of solvent and the NaBH4/HAuCl4 molar ratio (32 in ethaline and 5.2 in reline). High resolution transmission electron microscopy (HR-TEM) analysis of the gold nanowire networks showed clear lattice fringes of polycrystalline nanopowder of d = 2.36, 2.04, 1.44, and 1.23 angstrom corresponding to the (111), (200), (220), or (311) crystallographic planes of face centered cubic gold. The purified AuNWNs were used as catalysts for the chemical reduction of p-nitroaniline to diaminophenylene with sodium borohydride in aqueous solution. The reaction was monitored in real time by UV-vis spectroscopy. The results show that the reduction process is six times faster in the presence of gold nanowire networks stabilized by urea from the reline (AuNWN2) than in the presence of gold nanowire networks stabilized by ethylene glycol from ethaline (AuNWN1). This is due to a higher number of corners and edges on the gold nanowires synthesized in reline than on those synthesized in ethaline as proven by X-ray diffraction (XRD) patterns recorded for both types of gold nanowire networks. Nevertheless, both types of nanomaterials determined short times of reaction and high conversion of p-nitroaniline to diaminophenylene. These gold nanomaterials represent a new addition to a new generation of catalysts: gold based catalysts.