Kinetics and Morphological Analysis of Silver Platinum Bimetallic Nanoparticles Fredrick Okumu 1 • Mangaka Matoetoe 1 Received: 4 November 2015 / Revised: 7 January 2016 / Published online: 12 March 2016 Ó The Chinese Society for Metals and Springer-Verlag Berlin Heidelberg 2016 Abstract 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 H 2 PtCl 6 Á6H 2 O and AgNO 3 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. KEY WORDS: Platinum; Silver; Bimetallic nanoparticles; Kinetics; Morphology 1 Introduction Nanosized metals have attracted considerable interest because of their potential application in catalysis, micro- electronics, electronic, and magnetic devices [1]. Appli- cation limitations of nanomaterials may be due to metal oxidation resulting in loss of sensitivity (Fe, Co, and Ni) [1] and susceptibility to poisoning (Pt) [2]. Bimetallic synthesis emerged as a solution to these problems. Intro- duction of another metal to produce a bimetallic (BM) nanoparticle results in increased oxidation resistance while maintaining magnetic properties. BM materials also have improved activity, selectivity, and resistance to deactiva- tion as well as an increase in the diversity control of properties of interest. Multimetallic nanoparticles is an old subject [3]. How- ever, very limited investigation has been addressed to sensors [4, 5]. Interest in BM nanoclusters studies is due to their myriad properties and applications in optics [6], magnetism, catalysis [7], and others, mainly due to their high tenability and superior features compared with those of their monometallic counterparts [8]. Depending on the elements, relative concentrations, and details of the syn- thesis method, the BM may form core–shell structures, heterostructures, and ordered/random mixed-alloy nanocrystals, and this diversity increases the mass-specific activity (MSA) of the nanoparticles while also minimizing the production cost by using precious metals only in the surface of the particles [9, 10]. Available online at http://link.springer.com/journal/40195. & Mangaka Matoetoe lellangm@gmail.com 1 Department of Chemistry, Cape Peninsula University of Technology, Tennant Street, 652, Cape Town 8000, South Africa 123 Acta Metall. Sin. (Engl. Lett.), 2016, 29(4), 320–325 DOI 10.1007/s40195-016-0395-0