Kinetics and Morphological Analysis of Silver Platinum Bimetallic Nanoparticles

Kinetics of a one-pot core-shell synthesis of bimetallic (BM) silver-platinum (Ag-Pt) nanoparticles (NPs) by simultaneous reduction of 1:1 mol fraction of precursors H₂PtCl₆·6H₂O and AgNO₃ in aqueous solution is reported. Kinetics analysis was done by plotting UV-visible absorptions versus reaction time with a first-order fitting. Recorded constants of Ag NPs (0.079 s^-1), Ag-Pt NPs 1:1 (0.082 s^-1), and Pt NPs (0.006 s^-1) were obtained. The NPs suspension solutions were clear, free from AgCl precipitate, and had characteristic optical properties of 450 nm (Ag NPs), while there were no observable bands for Pt and BM NPs. Morphological analysis using transmission electron microscopy, energy-dispersive X-ray spectroscopy (EDX), and selected area electron diffraction (SAED) depicted spherical aggregates of Ag NPs, Pt NPs and core shell Pt-Ag NPs 1:1 of average size of 60, 2.5, and 20 mm, respectively. Presence of the Ag and Pt elemental composition in the nanoparticle suspensions was confirmed by EDX. SAED ring patterns revealed a single face-centered cubic crystalline nature of Ag NPs and showed typical Pt-based BMs randomly overlapped ring pattern with sharp diffraction spots.