Using three dimensions in catalytic mesoporous nanoarchitectures

Gold-titania (Au-TiO2) composite aerogels were synthesized, characterized, and tested as ambient-temperature oxidation catalysts for carbon monoxide. Adding alkanethiolate-monolayer-protected gold clusters (with similar to2-nm Au cores) directly to titania sol before gelation yields uniformly dispersed guests in the composite aerogel. The Au guests aggregate to similar to6 nm upon calcination to remove the alkanethiolate and crystallize amorphous titania to anatase. The resulting composite aerogel exhibits high catalytic activity toward CO oxidation at room temperature at Au particle sizes that are essentially inactive in prior Au-TiO2 catalysts. Transmission electron microscopy illustrates the three-dimensional nature of the catalytic nanoarchitecture in which the Au guests contact multiple anatase nanocrystallites.