Galvanic Replacement Methods in Nanostructure Synthesis

Galvanic replacement is a spontaneous redox process in which atoms are selectively oxidised and dissolved from a sacrificial template while ions of a more noble metal are concurrently reduced and deposited onto that template. Driven by differences in standard reduction potentials, this one‐pot approach enables atom‐by‐atom carving and regrowth, yielding hollow and multi‐shell architectures with finely tunable compositions, morphologies and surface chemistries. By selecting appropriate templates—often silver nanocubes, nanospheres or other colloidal seeds—and controlling reaction parameters such as precursor concentration, temperature and capping ligands, researchers can engineer nanocages, nanoboxes and porous frameworks that exhibit enhanced catalytic activity, strong plasmonic resonances or high surface area for biomedical delivery. The interplay between deposition kinetics and the nanoscale Kirkendall effect further allows precise control over wall thickness and internal cavity size. Galvanic replacement has thus emerged as a versatile bridge between chemical synthesis and electrochemical methods, offering scalable routes to bimetallic and alloy nanostructures for applications in sustainable catalysis, sensing platforms, photothermal therapy and energy conversion.

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A comprehensive account in 2023 recapitulates two decades of galvanic replacement synthesis, emphasising how the redox‐driven deposition on nanocrystalline templates can be harnessed to produce diverse metal nanostructures. It details mechanistic insights into site‐selected carving by surface capping agents, illustrating how Ag–Au and Pd–Pt systems yield hollow and alloyed architectures in a single step. The account further expands applications to nonmetallic substrates, demonstrating tunable Au and Pt nanostructures for catalysis and biomedicine and highlighting opportunities for shape‐directed plasmonic enhancement and drug delivery.

In 2024, an analytical chemistry study introduced bimetallic Au/Ag nanocubes with a controllable crescent‐arc facet via a combined galvanic replacement and co‐reduction strategy. By modulating the relative rates of oxidative dissolution and metal ion reduction, the authors achieved precise curvature and interparticle nanogaps, leading to ultra‐sensitive surface‐enhanced Raman scattering substrates. These nanocubes exhibited enhancement factors approaching 10¹¹ and enabled accurate detection of pesticide residues in complex matrices, underscoring the practical potential of morphology‐engineered galvanic replacement products for reliable chemical sensing.

Galvanic Replacement Methods in Nanostructure Synthesis publication trend

The graph below shows the total number of articles in galvanic replacement methods in nanostructure synthesis across all publications each year (not limited to Nature Index journals).

Technical terms

Galvanic replacement synthesis: A redox‐driven process where a less noble metal template is partly dissolved while ions of a more noble metal are reduced and deposited to form hollow or alloyed nanostructures.

Reduction potential: A measure of a species’ tendency to gain electrons; the difference between potentials of two metal couples drives galvanic replacement.

Nanoscale Kirkendall effect: Formation of voids within a template due to unequal diffusion rates of metal atoms and ions during galvanic replacement.

Capping agent: A molecule adsorbed on a growing nanoparticle surface that directs site‐selective deposition and controls final morphology.

Surface‐enhanced Raman scattering (SERS): An optical technique that exploits plasmonic nanostructures to amplify Raman signals of molecules located in nanoscale gaps or on roughened metal surfaces.

References

1. Galvanic Replacement Synthesis of Metal Nanostructures: Bridging the Gap between Chemical and Electrochemical Approaches. Accounts of Chemical Research (2023).
2. Plasmonic Nanocubes with a Controllable “Crescent Arc” Facet: Tunable Hotspot Engineering for Highly Reliable and Sensitive SERS Detection. Analytical Chemistry (2024).