Tappan B C, Huynh M H, Hiskey M A, Chavez D E, Luther E P, Mang J T, Son S F
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
J Am Chem Soc. 2006 May 24;128(20):6589-94. doi: 10.1021/ja056550k.
The synthesis of low-density, nanoporous materials has been an active area of study in chemistry and materials science dating back to the initial synthesis of aerogels. These materials, however, are most often limited to metal oxides, e.g., silica and alumina, and organic aerogels, e.g., resorcinol/formaldehyde, or carbon aerogels, produced from the pyrolysis of organic aerogels. The ability to form monolithic metallic nanocellular porous materials is difficult and sometimes elusive using conventional methodology. Here we report a relatively simple method to access unprecedented ultralow-density, nanostructured, monolithic, transition-metal foams, utilizing self-propagating combustion synthesis of novel transition-metal complexes containing high nitrogen energetic ligands. During the investigation of the decomposition behavior of the high-nitrogen transition metal complexes, it was discovered that nanostructured metal monolithic foams were formed in a post flame-front dynamic assembly having remarkably low densities down to 0.011 g cm(-3) and extremely high surface areas as high as 270 m(2) g(-1). We have produced monolithic nanoporous metal foams via this method of iron, cobalt, copper, and silver metals. We expect to be able to apply this to many other metals and to be able to tailor the resulting structure significantly.
低密度纳米多孔材料的合成一直是化学和材料科学领域的一个活跃研究方向，其历史可追溯到气凝胶的最初合成。然而，这些材料大多局限于金属氧化物，如二氧化硅和氧化铝，以及有机气凝胶，如间苯二酚/甲醛气凝胶，或由有机气凝胶热解产生的碳气凝胶。使用传统方法形成整体式金属纳米多孔材料的能力很困难，有时甚至难以实现。在此，我们报告一种相对简单的方法，利用含有高氮高能配体的新型过渡金属配合物的自蔓延燃烧合成，来制备前所未有的超低密度、纳米结构的整体式过渡金属泡沫。在研究高氮过渡金属配合物的分解行为时，发现纳米结构的金属整体泡沫在火焰前沿后的动态组装过程中形成，其密度低至0.011 g cm⁻³，表面积极高，高达270 m² g⁻¹。我们通过这种方法制备了铁、钴、铜和银金属的整体式纳米多孔金属泡沫。我们期望能够将此方法应用于许多其他金属，并能够显著调整所得结构。
