Highly Quasi-Monodisperse Ag Nanoparticles on Titania Nanotubes by Impregnative Aqueous Ion Exchange

• Published in: Langmuir Vol. 25; no. 17; pp. 10195 - 10201
• Main Authors: Toledo-Antonio, J. A, Cortes-Jácome, M. A, Angeles-Chavez, C, López-Salinas, E, Quintana, P
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-09-2009
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Materials: Nano-and Mesostructured Materials, Polymers, Gels, Liquid Crystals, Composites; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Surface physical chemistry; Binary compound; Incorporation; Annealing; Heat treatment; Methodology; Support; Nanoparticle; Transition element compounds; Nanotube; Electron transfer; Strong interaction; Ions; Transition metal; Agglomeration; Silver nitrate; Chemical reduction; Silver; Particle size distribution; Monodispersed particle; Light absorption; Ion exchange; Titanium oxide; Charge transfer; Hydrothermal condition
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la9009702

Silver nanoparticles were homogenously dispersed on titania nanotubes (NT), which were prepared by alkali hydrothermal methodology and dried at 373 K. Ag+ incorporation was done by impregnative ion exchange of aqueous silver nitrate onto NT. First, Ag+ ions incorporate into the layers of nanotube walls, and then, upon heat treatment under N2 at 573 and 673 K, they migrate and change into Ag2O and Ag0 nanoparticles, respectively. In both cases, Ag nanoparticles are highly dispersed, decorating the nanotubes in a polka-dot pattern. The Ag particle size distribution is very narrow, being ca. 4 ± 2 nm without any observable agglomeration. The reduction of Ag2O into Ag0 octahedral nanoparticles occurs spontaneously and topotactically when annealing, without the aid of any reducing agent. The population of Ag0 nanoparticles can be controlled by adjusting the annealing temperature. An electron charge transfer from NT support to Ag0 nanoparticles, because of a strong interaction, is responsible for considerable visible light absorption in Ag0 nanoparticles supported on NT.