Influence of Size and Composition on the Transformation Mechanicsof Gold-Silver Core-Shell Nanoparticles

JI Peters and LS Tang and OU Uche, JOURNAL OF PHYSICAL CHEMISTRY C, 126, 6612-6618 (2022).

DOI: 10.1021/acs.jpcc.1c10891

Bimetallic nanoparticles occupy a unique space in thefield ofmaterials science as they display physical and optoelectronic properties thatare absent in their monometallic counterparts. These attributes increase theirapplicability in niche processes where they can perform distinct functionsfrom those achievable with the corresponding pure-element particles. In thecurrent work, we explore the feasibility of performing structural character-ization of gold-silver core-shell nanoclusters as well as analyze thetransformation between cuboctahedral and icosahedral geometries using acombination of atomistic simulations and electronic structure calculations.Wefind that size may be a limiting factor in distinguishing between the abovetwo geometries when theoretical vibrational densities of states are employedin characterizing the nanoparticles under consideration. The results from ourdensity functional theory calculations also reveal that the transformation between cuboctahedral and icosahedral geometries occursvia a martensitic, symmetric mechanism for the 147-atom and 309-atom nanoclusters. In addition, the associated transformationbarriers for the bimetallic core-shell particles are strongly size-dependent and typically increase with the composition of silver in thenanocluster.

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