Deciphering the Surface Composition and the Internal Structure of Alloyed Silver-Gold Nanoparticles.

['Grasmik V', 'Rurainsky C', 'Loza K', 'Evers MV', 'Prymak O', 'Heggen M', 'Tschulik K', 'Epple M']
Chemistry. 2018 Mar 9. doi: 10.1002/chem.201800579. [Epub ahead of print]

Author information
['University of Duisburg-Essen, Inorganic Chemistry, Universitaetsstr. 5-7, 45117, Essen, GERMANY.', 'Ruhr University Bochum, Faculty of Chemistry and Biochemistry, 44780, Bochum, GERMANY.', 'Forschungszentrum Julich Peter Grunberg Institut, Ernst Ruska Centre, 52425, Juelich, GERMANY.', 'Ruhr-Universitat Bochum, Faculty of Chemistry and Biochemistry, 44780, Bochum, GERMANY.', 'Universität Duisburg-Essen, Institut für Anorganische Chemie, Universitätsstr. 5-7, 45117, Essen, GERMANY.']

Abstract
['Spherical bimetallic AgAu nanoparticles in the molar ratios 30:70, 50:50, and 70:30 with a diameter of 30 to 40 nm were analyzed together with pure silver and gold nanoparticles of the same size. Dynamic light scattering (DLS) and differential centrifugal sedimentation (DCS) were used for size determination. Cyclic voltammetry (CV) was used to determine the nanoalloy composition, together with atomic absorption spectroscopy (AAS), energy-dispersive X-ray spectroscopy (EDX) and Ultraviolet-visible (UV/vis) spectroscopy. Underpotential deposition (UPD) of lead (Pb) on the particle surface gave information about its spatial elemental distribution and surface area. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) were applied to study the shape and the size of the nanoparticles. X-ray powder diffraction gave the crystallite size and the microstrain. The particles form a solid solution (alloy) with an enrichment of silver on the nanoparticle surface, including some silver-rich patches. UPD indicated that the surface only consists of silver atoms.']