Preparation of highly controlled nanostructured Au within mesopores using reductive deposition in non-polar environments

This paper describes a sophisticated and unique method of Au deposition exclusively inside mesoporous silica, in clear contrast to general methods requiring surface modification with organic functional groups interacting with Au. Reductive deposition using hexane and 1,1,3,3-tetramethydisiloxane as solvent and reducing agent, respectively, was very successful in the inside deposition of Au in two-dimensional hexagonal mesoporous silica (SBA-15). This result was attributed to the suppression of the migration of Au species (Au ions, atoms, and clusters) inside SBA-15 by forcibly locating Au species near the relatively polar mesopore surfaces in the presence of highly non-polar compounds in the mesochannels. Au nanorods replicated from the pore shape of SBA-15 were prepared by reductive deposition, while Au nanoparticles were selectively formed by performing the deposition in the presence of hexadecyltrimethylammonium bromide, which shows promise in the further development of precise design strategies for nanostructured Au.