Morphology Control of Platinum Particles Grown on a Liquid Metal Interface

Area of Science:

• Electrochemistry
• Materials Science
• Nanotechnology

Background:

• Galvanic replacement reaction (GRR) is a key method for creating complex heterostructures.
• Controlled synthesis of noble metal nanoparticles on liquid metal (LM) surfaces is challenging.

Purpose of the Study:

• Investigate GRR on gallium-based LM using platinum precursors with varying chloride coordination.
• Demonstrate coordination environment as a tool to control Pt nucleation and growth.
• Explore LM droplet evolution and macroscopic transformations driven by Pt deposition.

Main Methods:

• Systematic investigation of GRR between LM droplets and K2PtCl4 (tetra-coordinated) and K2PtCl6/(NH4)2PtCl6 (hexa-coordinated) platinum precursors.
• Analysis of thermodynamic driving forces and kinetic pathways.
• Characterization of resulting Pt nanoparticle morphologies and spatial distributions.
• Observation of LM droplet evolution and macroscopic transformations.

Main Results:

• Pt precursor coordination environment effectively regulates Pt nucleation and growth.
• [PtCl4]2- yielded uniformly distributed, satellite-like Pt domains.
• [PtCl6]2- resulted in sparsely localized, patch-like Pt deposits.
• Distinct Pt morphologies modulated interfacial stress, influencing LM droplet evolution.
• LM surface oxide layer and Pt-catalyzed hydrogen evolution were key factors in LM transformations.

Conclusions:

• Coordination tuning provides a strategy for designing noble-metal-coated LM heterostructures.
• Tailored morphologies and spatial distributions of Pt nanoparticles were achieved.
• This approach enables the development of reconfigurable functional materials.
• Deepened fundamental understanding of LM-based GRR mechanisms.