Salt-Mediated Self-Assembly of Metal Nanoshells into Monolithic Aerogel Frameworks

Bimetallic alloy aerogels (Au/Ag, Pd/Ag, Pt/Ag) have been prepared from a novel approach that involves the salt-mediated self-assembly of metal nanoshells followed by supercritical drying. These materials can be prepared as large (centimeter to inch) self-supported monoliths within a day, and the gelation kinetics can be tuned by engineering the in-situ-generated ionic strength of the precursor colloids. Resultant aerogels exhibit a continuous mesopore-to-macropore network that can be altered by the inner diameter of the precursor nanoshells and the accessibility of molecules to the inner surface of the hollows, offering new perspectives for their applications in advanced technologies. The attractive nature of this new strategy is the ability to increase the rate of self-assembly, which otherwise is an intrinsically sluggish process in the oxidation-induced NP assembly reported to date.