(398c) Galvanic Synthesis of Porous Metal Nanostructures Using Aluminum Nanoparticle Template

Galvanic replacement reaction has been used to synthesize various metal nanostructures, in which a more cathodic (less active) metal replaces a more anodic (active) metal (template material). Up to date, silver (Ag), copper (Cu), tin (Sn), and cobalt (Co) have been used as template materials to fabricate new nanomaterials and nanostructures, which have found such applications as nanocatalysts, nanosensors, controlled release and biomedical imaging. In this presentation, we show that a wide variety of porous metal nanostructures, including porous nanoparticles and porous microparticles, can be fabricated by the galvanic replacement reaction using aluminum (Al) nanoparticle template.  The template particle, aluminum nanoparticle, owing to its very low redox potential (-1.66 V vs standard hydrogen electrode, SHE), can be replaced by such metals as nickel (Ni), iron (Fe), Co, copper (Cu), platinum (Pt), palladium (Pd), Ag, and gold (Au). Various porous metal nanostructures have been formed with this new template material, including individual discrete porous particles, 3-D “coral” networks, and larger porous particles.  It was found that the growth kinetics play an important role in the formation of the porous nanostructures. Scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive x-ray spectroscopy (EDS), and X-ray diffraction (XRD) are used to determine the element and structure of these porous nanostructures. These porous nanostructures have promise as nanocatalysts for various reactions or electrochemical sensors for biomolecular detection.