Template Regeneration in Galvanic Replacement: A Route to Highly Diverse Hollow Nanostructures

The ability to produce a diverse spectrum of hollow nanostructures is central to the advances in many current and emerging areas of technology. Herein, we report a general method to craft hollow nanostructures with highly tunable physical and chemical parameters. The key strategy is to regenerate the nanoscale sacrificial templates in a galvanic replacement reaction through site-selective overgrowth. As examples, we demonstrate the syntheses of nanocages and nanotubes made of silver, gold, palladium, and/or platinum with well-controlled wall thicknesses and elemental distributions. Using the nanocages of silver and gold as models, we demonstrate they possess intriguing plasmonic properties and offer superior performance in biosensing applications. This study provides a powerful platform to customize hollow nanostructures with desired properties and therefore is expected to enable a variety of fundamental studies and technologically important applications.