AgCl and Ag/AgCl hollow spheres based on self-assemblies of a multi-amine head surfactant

A simple method for fabricating Ag/AgCl hollow spheres was developed by using a multi-amine head surfactant C18N3 as a soft template. After adding AgNO3 to micelles of C18N3 dispersed in HCl solution, Ag/AgCl hollow spheres were formed with diameters ranging from 100 nm to 1200 nm which were a function of aging time. The mechanical strength of the formed spheres was found to be very good, probably due to the uniquely structured C18N3 surfactant as well as the reinforcement effect of Ag/AgCl on the NH2 terminal groups. The active species on the surfaces of hollow spheres, Ag+ and Cl-, remained almost unchanged when exposed to natural daylight for more than I year, showing a very good stability against light and environmental reduction. However, the obtained Ag+ species on the surface could be transformed into Ag-0 quickly with high yield (ca. 90%) under UV light irradiation. The transfer process was studied by EDX spectra at different irradiation times. Thus the Ag/AgG hollow spheres may serve as useful precursors for many other noble metallic hollow spheres because Ag could be replaced by other noble metals such as Au and Pt with the aid of the galvanic replacement reaction. (C) 2009 Elsevier Inc. All rights reserved.