title: In Situ Synthesis of Gold Nanoparticles without Aggregation in the Interlayer Space of Layered Titanate Transparent Films.
abstract: Combinations of metal oxide semiconductors and gold nanoparticles (AuNPs) have been investigated as new types of materials. The in situ synthesis of AuNPs within the interlayer space of semiconducting layered titania nanosheet (TNS) films was investigated here. Two types of intermediate films (i.e., TNS films containing methyl viologen (TNS/MV2+) and 2-ammoniumethanethiol (TNS/2-AET+)) were prepared. The two intermediate films were soaked in an aqueous tetrachloroauric(III) acid (HAuCl4) solution, whereby considerable amounts of Au(III) species were accommodated within the interlayer spaces of the TNS films. The two types of obtained films were then soaked in an aqueous sodium tetrahydroborate (NaBH4) solution, whereupon the color of the films immediately changed from colorless to purple, suggesting the formation of AuNPs within the TNS interlayer. When only TNS/MV2+was used as the intermediate film, the color of the film gradually changed from metallic purple to dusty purple within 30 min, suggesting that aggregation of AuNPs had occurred. In contrast, this color change was suppressed by using the TNS/2-AET+intermediate film, and the AuNPs were stabilized for over 4 months, as evidenced by the characteristic extinction (absorption and scattering) band from the AuNPs.
authors.affiliation: Department of Material Science and Technology, Faculty of Engineering, Niigata University.
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Sasaki
authors.affiliation: Department of Material Science and Technology, Faculty of Engineering, Niigata University.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Matsubara
authors.affiliation: Department of Material Science and Technology, Faculty of Engineering, Niigata University.
authors.forename: Shiori
authors.initials: S
authors.lastname: Kawamura
authors.affiliation: Department of Material Science and Technology, Faculty of Engineering, Niigata University.
authors.forename: Kenji
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Material Science and Technology, Faculty of Engineering, Niigata University.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yagi
authors.affiliation: Department of Material Science and Technology, Faculty of Engineering, Niigata University; yui.t@eng.niigata-u.ac.jp.
authors.forename: Tatsuto
authors.initials: T
authors.lastname: Yui
mesh_terms: D003116:Color; D006046:Gold; D053768:Metal Nanoparticles / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*
chemical_list: D010087:Oxides; C009495:titanium dioxide; D006046:Gold; D014025:Titanium