Kinetically Controlled Seed-Mediated Synthesis of Colloidal Copper Nanotetrahedra with Intricate Internal Structure

Area of Science:

• Nanochemistry
• Materials Science
• Catalysis

Background:

• Controlled synthesis of non-noble metal nanocrystals, like copper, is challenging due to limited mechanistic understanding.
• Achieving well-defined shapes and internal structures in copper nanocrystals is a key goal in nanochemistry.

Purpose of the Study:

• To develop a heterometallic seed-mediated synthesis for monodisperse, size-tunable copper truncated bitetrahedra and tetrahedra.
• To understand the nucleation and growth pathways of copper nanocrystals using gold seeds.

Main Methods:

• Heterometallic seed-mediated synthesis using preformed gold nanocrystals.
• Systematic variation of gold seed concentration to control nanocrystal size.
• Electron microscopy and four-dimensional scanning transmission electron microscopy for structural analysis.
• Electron energy-loss spectroscopy and electromagnetic simulations for plasmon mode analysis.

Main Results:

• Achieved monodisperse, size-tunable copper truncated bitetrahedra and tetrahedra.
• Demonstrated that penta-twinned gold seeds induce asymmetric copper overgrowth and twin boundaries.
• Observed unique structural features in copper tetrahedra, including twinned layers and 5-fold axes.
• Copper nanocrystals exhibited size-dependent localized surface plasmon resonance and excellent surface-enhanced Raman scattering activity.

Conclusions:

• Heterometallic twinned seeds effectively direct the synthesis of low-symmetry copper nanocrystals.
• The developed method offers new opportunities for designing non-noble metal nanocrystals with tailored optical and catalytic properties.
• This approach advances the synthesis of functional nanomaterials for advanced applications.