A Comparative Study of Galvanic Replacement Reactions Involving Ag Nanocubes and AuCl2− or AuCl4−

The galvanic replacement reaction provides a simple and effective method for preparing hollow nanostructures of noble metals including Au, Pd, and Pt when Ag nanostructures are used as sacrificial templates.[1] These hollow nanostructures are enclosed by continuous or porous walls with a tunable/controllable thickness. For Au-based hollow nanostructures such as nanoboxes and nanocages, reduction of the wall thickness would lead to a red-shift for the localized surface plasmon resonance (LSPR) peak.[2] Significantly, when the LSPR peak is tuned into the near-infrared region from 800 to 900 nm (the so-called transparent window of soft tissues), these nanostructures hold great promise for a variety of biomedical applications that may include drug delivery,[3] contrast-enhanced optical imaging,[4] and photothermal therapy.[5]