Dopant-controlled selenization in Pd nanocrystals: the triggered Kirkendall effect

Area of Science:

• Materials Science and Engineering
• Nanotechnology
• Chemical Engineering

Background:

• Doping foreign impurities into host nanomaterials can create novel material properties and influence crystallization, shape, and phase.
• While dopant effects on material properties are well-researched, the chemistry of doping in nanostructure design remains underexplored.
• Understanding doping chemistry is crucial for designing advanced nanomaterials with tailored characteristics.

Purpose of the Study:

• To investigate dopant-controlled enhancement of chemical reaction rates during material transformation.
• To examine the effect of doping on the shape evolution of nanostructures.
• To elucidate the fundamental role of dopants in controlling chemical processes and crystal growth.

Main Methods:

• Selenization of metal palladium (Pd(0)) nanocrystals.
• Utilized silver (Ag) as a dopant to study its effect on the reaction.
• Detailed investigations using advanced characterization techniques to analyze structural and chemical changes.

Main Results:

• Doping with Ag significantly enhanced the selenization rate of Pd(0) by over 30 times compared to undoped samples.
• Undoped selenization produced cuboidal Pd17Se15, while Ag-doped Pd(0) resulted in hollow cubic Pd17Se15 nanostructures.
• Doping induced uniform, all-around selenization and triggered the Kirkendall effect, leading to hollow structures, unlike the unidirectional process in undoped nanocrystals.

Conclusions:

• Dopants play a critical role in controlling chemical reaction rates and directional growth during nanomaterial synthesis.
• The study demonstrates a novel method for creating hollow nanostructures through dopant-controlled selenization.
• Findings broaden the understanding of doping chemistry in nanostructure design and crystal growth, opening new avenues for materials innovation.