Formation of Mixed Bimetallic Nanoparticles of Immiscible Metals through Plasma-Induced Reduction of Precursors in Solutions: A Case Study of Ag-Pt Alloy Nanoparticles

Bimetallic alloy nanomaterials exhibitpromising propertiesinvarious applications. The synthesis of these nanomaterials is oftenchallenging due to the immiscibility of the metals forming the alloy.To overcome this issue, complex synthetic strategies, relying on difficult-to-controlreduction conditions, have been utilized, showing that rapid reductionand quenching are required to kinetically trap immiscible metal atomsin single nanoparticles. In this study, we demonstrate a simpler syntheticstrategy to form well-mixed bimetallic nanoparticles of immisciblemetals. We exploit the interactions between pulsed plasma and solutionscharged with metal precursor salts to rapidly form metal atoms. Wedemonstrate that the minimal requirements for the formation of alloysinclude the following: (i) the metal precursor reduction rates arehigh enough to allow the kinetic trapping of alloy nanoparticles,(ii) the reduction rates are similar for the respective metal precursors,ensuring a consistent mixing during the growth process, and (iii)the nucleation process is controlled to avoid the "burst nucleation"which takes place when the local concentrations of reduced metal atommonomers exceed a critical threshold.