Electronic connection to the interior of a mesoporous insulator with nanowires of crystalline RuO2

Highly porous materials such as mesoporous oxides are of technological inte rest(1) for catalytic, sensing and remediation applications: the mesopores (of size 2-50 nm) permit ingress by molecules and guests that are physicall y excluded from microporous materials. Connecting the interior of porous ma terials with a nanoscale or 'molecular' wire would allow the direct electro nic control (and monitoring) of chemical reactions and the creation of nano structures for high-density electronic materials(2). The challenge is to cr eate an electronic pathway (that is a wire) within a mesoporous platform wi thout greatly occluding its free volume and reactive surface area(3). Here we report the synthesis of an electronically conductive mesoporous composit e-by the cryogenic decomposition of RuO4-on the nanoscale network of a part ially densified silica aerogel. The composite consists of a three-dimension al web of interconnected (similar to 4-nm in diameter) crystallites of RuO2 , supported conformally on the nanoscopic silica network. The resulting mon olithic (RuO(2)parallel to SiO2) composite retains the free volume of the a erogel and exhibits pure electronic conductivity. In addition to acting as a wired mesoporous platform, the RuO2-wired silica aerogel behaves as a por ous catalytic electrode for the oxidation of chloride to molecular chlorine .