Abstract
Ag 2 O nanocubes, rhombicuboctahedra, octahedra, and hexapods have been employed as templates for the generation of Ag 2 O-Ag 2 S core-shell structures through a rapid sulfidation process in a basic solution. Addition of an ammonia etching solution quickly removes the Ag 2 O cores, thereby resulting in the formation of Ag 2 S cages with morphologies that resemble the starting templates. The composition of the Ag 2 S shells and cages has been extensively determined by various analytical techniques including X-ray and electron diffraction and X-ray photoelectron spectroscopy. The Ag 2 S shells have a monoclinic crystal structure and are polycrystalline with some amorphous and porous regions. The nanocage formation process has been captured by transmission electron microscopy (TEM). Gap spaces are formed initially between the cores and the shells owing to uniform etching of the Ag 2 O cores on all of the faces. No linkages connecting the cores to the shells have been observed. Depending on the potential scanning ranges applied, four types of electrochemical redox behavior have been identified for the Ag 2 O and Ag 2 O-Ag 2 S cubes in a basic solution. The ability to easily fabricate thin sheets of Ag 2 S over different Ag 2 O surfaces should extend the applications of Ag 2 S nanostructures. Be on etch: Large polyhedral Ag 2 S cages (bottom) with thin shells can be readily obtained by first forming a sulfide layer over various polyhedral Ag 2 O crystal templates (top) such as cubes, octahedra, and hexapods through a rapid sulfidation process, and subsequent treatment with an ammonia solution to remove the Ag 2 O cores; the Ag 2 S cages retain the morphologies of the original templates (scale bar=500 nm). Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.