Ryan JV, Berry AD, Anderson ML, Long JW, Stroud RM, Cepak VM, Browning VM, Rolison DR, Merzbacher CI
Naval Research Laboratory, Washington, DC 20375, USA.
Nature. 2000 Jul 13;406(6792):169-72. doi: 10.1038/35018040.
Highly porous materials such as mesoporous oxides are of technological interest for catalytic, sensing and remediation applications: the mesopores (of size 2-50 nm) permit ingress by molecules and guests that are physically excluded from microporous materials. Connecting the interior of porous materials with a nanoscale or 'molecular' wire would allow the direct electronic control (and monitoring) of chemical reactions and the creation of nanostructures for high-density electronic materials. The challenge is to create an electronic pathway (that is, a wire) within a mesoporous platform without greatly occluding its free volume and reactive surface area. Here we report the synthesis of an electronically conductive mesoporous composite--by the cryogenic decomposition of RuO4--on the nanoscale network of a partially densified silica aerogel. The composite consists of a three-dimensional web of interconnected (approximately 4-nm in diameter) crystallites of RuO2, supported conformally on the nanoscopic silica network. The resulting monolithic (RuO2//SiO2) composite retains the free volume of the aerogel and exhibits pure electronic conductivity. In addition to acting as a wired mesoporous platform, the RuO2-wired silica aerogel behaves as a porous catalytic electrode for the oxidation of chloride to molecular chlorine.
高度多孔的材料，如介孔氧化物，在催化、传感和修复应用方面具有技术吸引力：介孔（尺寸为2 - 50纳米）允许那些被微孔材料物理排斥的分子和客体进入。将多孔材料的内部与纳米级或“分子”导线连接起来，将能够对化学反应进行直接的电子控制（和监测），并为高密度电子材料创建纳米结构。挑战在于在介孔平台内创建一条电子通路（即导线），而不会过度堵塞其自由体积和反应表面积。在此，我们报告了通过RuO₄的低温分解，在部分致密化的二氧化硅气凝胶的纳米级网络上合成一种导电介孔复合材料。该复合材料由相互连接的（直径约4纳米）RuO₂微晶的三维网络组成，这些微晶共形地支撑在纳米级二氧化硅网络上。所得的整体式（RuO₂//SiO₂）复合材料保留了气凝胶的自由体积，并表现出纯电子导电性。除了作为一个有线介孔平台外，RuO₂连接的二氧化硅气凝胶还作为一种多孔催化电极，用于将氯化物氧化为分子氯。
