Template-Engaged Replacement Reaction:  A One-Step Approach to the Large-Scale Synthesis of Metal Nanostructures with Hollow Interiors

This paper describes a general approach that generates nanoscale hollow structures of metals by reacting solutions of appropriate salt solutions with solid templates of a more reactive metal. Typical examples include Au3+, Pt2+, and Pd2+ salts and nanoparticles or nanowires of silver. The morphology, void space, and wall thickness of these hollow structures are all determined by the solid templates, which are completely converted into soluble species during the replacement reaction. Both electron microscopy and diffraction studies indicate that single crystalline hollow structures of metals can also be obtained when the templates are single crystals. These metallic hollow structures, having well-controlled sizes and shapes, are expected to find use in a number of applications that involve nanoscale encapsulation, drug delivery, plasmon photonics, and calorimetric sensing.