Gold Silver Core Shell Nanoparticles (Au/ Ag, 99.99%, APS: 80-100nm, Metal Core/ Metal Shell)

Gold Silver Core-Shell Nanoparticles

Applications

Plasmonic and Optical Applications

Surface Enhanced Raman Spectroscopy (SERS): Au-Ag core-shell nanoparticles are used extensively in SERS, a technique that enhances the Raman scattering of molecules near metal surfaces. The plasmonic properties of gold and silver can lead to a stronger SERS signal compared to nanoparticles of a single metal. The silver shell enhances the local electric field near the nanoparticle surface, increasing the sensitivity and enabling the detection of low-concentration analytes, such as biomarkers, pollutants, or drugs. This makes Au-Ag nanoparticles ideal for diagnostic applications, environmental monitoring, and forensics.

Localized Surface Plasmon Resonance (LSPR): Both gold and silver are known for their plasmonic behavior, which arises from the oscillation of conduction electrons when exposed to light. The core-shell structure allows for enhanced LSPR effects due to the combined plasmonic properties of the metals. These nanoparticles can be tuned to specific wavelengths of light, making them useful in biosensing and bioimaging. By adjusting the ratio of gold to silver and varying the size and shape of the nanoparticles, the plasmonic resonance can be engineered for specific applications.

Photothermal Therapy: The plasmonic heating capabilities of gold and silver can be leveraged in photothermal therapy (PTT), where nanoparticles absorb light (especially in the near-infrared spectrum) and convert it to heat. This heat can be used to selectively destroy cancer cells. Au-Ag nanoparticles are particularly attractive for this application because they can be engineered to exhibit enhanced optical absorption and more efficient energy conversion compared to single-metal nanoparticles, leading to more effective tumor treatment.

Catalysis

Electrocatalysis: The core-shell structure of Au-Ag nanoparticles enhances their electrocatalytic activity in reactions like oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), and fuel cell reactions. Silver, when coated onto gold, can promote electron transfer and reduce the energy barriers for these reactions, making Au-Ag core-shell nanoparticles valuable for energy conversion technologies such as fuel cells and batteries.

Catalysis in Organic Reactions: Gold and silver are both active catalysts in various organic reactions, such as oxidation, reduction, and hydrogenation. The synergistic effects between the gold core and silver shell can enhance the catalytic efficiency, stability, and selectivity of the nanoparticles. For example, Au-Ag core-shell nanoparticles are used in CO oxidation, dehydrogenation of alcohols, and C-H activation reactions. The silver shell can influence the electronic structure of the gold core, making the overall catalyst more active and durable under harsh conditions.

Environmental Catalysis: These nanoparticles are also studied for their ability to degrade environmental pollutants, such as organic dyes and heavy metals, due to their high surface area and catalytic activity. The silver shell can help accelerate the degradation process by promoting the adsorption and transformation of pollutants, while the gold core ensures the stability and longevity of the nanoparticles.

Biosensing and Diagnostics

Biosensors: The combination of gold’s biocompatibility and silver’s chemical reactivity makes Au-Ag core-shell nanoparticles ideal for biosensing applications. They can be functionalized with biomolecules, such as antibodies, aptamers, or peptides, to selectively capture target analytes (e.g., proteins, DNA, viruses, or other biomolecules). The plasmonic properties of gold and silver enable highly sensitive detection of these analytes through SPR-based sensors, colorimetric assays, or SERS.