Multimetallic Aerogels by Template-Free Self-Assembly of Au, Ag, Pt, and Pd Nanoparticles
Multimetallic Aerogels by Template-Free Self-Assembly of Au, Ag, Pt, and Pd Nanoparticles
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DOI：
10.1021/cm4033258
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发表时间：
2014-01-28
影响因子：
8.6
通讯作者：
Eychmueller, Alexander
中科院分区：
文献类型：
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作者：
Herrmann, Anne-Kristin;Formanek, Petr;Eychmueller, Alexander
纳米结构的多孔金属引起了材料科学家的极大兴趣，因为它们联合收割机了高表面积，透气性，导电性，等离子体行为和尺寸增强的催化反应性。在这里，我们提出了形成多金属多孔三维网络的无模板自组装过程。纳米链是由Au、Ag、Pt和Pd纳米颗粒在水介质中受控聚结而形成的，并且它们的互连和相互渗透导致形成自支撑网络。通过超临界干燥技术将所得贵金属凝胶转化为固体气凝胶。与以前报道的结果相比，该技术是方便的排除额外的不稳定。此外，温度控制被证明是一个强大的工具，允许加速凝胶化过程以及改善其重现性和适用性。电子显微镜显示了网络的纳米结构及其高孔隙率。利用XRD和EDX STEM研究了该气凝胶的合金化行为，证明了温度诱导的相变化对合金化状态的控制。此外，与通过其他方法获得的多孔贵金属相比，所得多金属气凝胶显示出极低的相对密度（50 m2/g）。描述了导电薄膜以及具有有机聚合物的混合材料以强调材料的可加工性，这是关于处理易碎结构和集成到器件架构中的关键因素。多金属气凝胶由于其优异的可调性质，在多相催化、电催化、储氢、传感器等领域有着广泛的应用前景，同时也在表面增强拉曼光谱（Sers）和透明导电基底的制备等方面有着重要的应用前景。
Nanostructured, porous metals are of great interest for material scientists since they combine high surface area, gas permeability, electrical conductivity, plasmonic behavior, and size-enhanced catalytic reactivity. Here we present the formation of multimetallic porous three-dimensional networks by a template-free self-assembly process. Nanochains are formed by the controlled coalescence of Au, Ag, Pt, and Pd nanoparticles in aqueous media, and their interconnection and interpenetration leads to the formation of a self-supporting network. The resulting noble-metal-gels are transformed into solid aerogels by the supercritical drying technique. Compared to previously reported results, the technique is facilitated by exclusion of additional destabilizers. Moreover, temperature control is demonstrated as a powerful tool, allowing acceleration of the gelation process as well as improvement of its reproducibility and applicability. Electron microscopy shows the nanostructuring of the network and its high porosity. XRD and EDX STEM are used to investigate the alloying behavior of the bimetallic aerogels and prove the control of the alloying state by temperature induced phase modifications. Furthermore, the resulting multimetallic aerogels show an extremely low relative density (50 m(2)/g) compared to porous noble metals obtained by other approaches. Electrically conductive thin films as well as hybrid materials with organic polymers are depicted to underline the processability of the materials, which is a key factor regarding handling of the fragile structures and integration into device architectures. Owing to their exceptional and tunable properties, multimetallic aerogels are very promising materials for applications in heterogeneous catalysis and electrocatalysis, hydrogen storage, and sensor systems but also in surface enhanced Raman spectroscopy (SERS) and the preparation of transparent conductive substrates.