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Formation and characterization of Au–Ag bimetallic nanoparticles in water-in-oil microemulsions
Dong-Hwang Chen,Cheng Jia Chen +1 more
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In this article, gold-silver bimetallic nanoparticles with varying mole fractions were synthesized in water-in-oil microemulsions of water/Aerosol OT/isooctane by the coreduction of HAuCl4 and AgNO3 with hydrazine at 25 °C.Abstract:
Gold–silver bimetallic nanoparticles with varying mole fractions were synthesized in water-in-oil microemulsions of water/Aerosol OT/isooctane by the co-reduction of HAuCl4 and AgNO3 with hydrazine at 25 °C. TEM analysis revealed that the bimetallic nanoparticles were essentially monodisperse and had a mean diameter of 4–22 nm, increasing with an increase in the molar ratio of water to Aerosol OT (ω0) and Ag content. The UV/VIS absorption spectra of their solutions exhibited only one plasmon absorption and the absorption maximum of the plasmon band red-shifted almost linearly from 400 to 520 nm with increasing Au ∶ Ag molar ratio, revealing the formation of an alloy. Although the characteristic peaks for Au and Ag were too close to distinguish, the XRD analysis showed that the characteristic peaks for a Au–Ag bimetallic systems became broader and accordingly suggested the formation
of bimetallic nanoparticles. The EDX analysis confirmed directly the formation of Au–Ag bimetallic nanoparticles. It showed that the composition of Au–Ag bimetallic nanoparticles was in good agreement with that of the feed solution but the outer layer of the particles was enriched in Ag. The HRTEM study indicated the resultant Au–Ag bimetallic nanoparticles contained single and multiple twins as well as stacking faults, and no mismatch was present. In addition, it was found that the formation rate of Au nanoparticles was much faster than that of Ag nanoparticles. This satisfactorily accounted for the composition distribution within a Au–Ag bimetallic nanoparticle.read more
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A simple and green method for the synthesis of Au, Ag, and Au-Ag alloy nanoparticles
TL;DR: In this paper, an environmentally benign method for the preparation of Au, Ag, and Au-Ag nanoparticles in water, using glucose as the reducing agent and starch as the protecting agent, was reported.
Journal ArticleDOI
Solution-Phase Synthesis of Sub-10 nm Au−Ag Alloy Nanoparticles
TL;DR: In this article, the plasmon absorption band of Ag−Au nanoparticles shifts linearly to the red with increasing Au content, and the authors concluded that the nanoparticles are alloys, rather than core−shell composites.
Journal ArticleDOI
Methods and strategies for the synthesis of diverse nanoparticles and their applications: a comprehensive overview
Chetna Dhand,Neeraj Dwivedi,Xian Jun Loh,Alice Ng Jie Ying,Navin Kumar Verma,Roger W. Beuerman,Rajamani Lakshminarayanan,Seeram Ramakrishna +7 more
TL;DR: A comprehensive overview on various physical, chemical and bio-assisted methods largely employed to synthesize and fabricate NPs of varying size, surface characteristics, functionalities and physicochemical behavior is provided in this paper.
Journal ArticleDOI
Microemulsion method: A novel route to synthesize organic and inorganic nanomaterials
TL;DR: In this paper, the use of microemulsions for synthesizing and controlling the grain size and morphology of the nanoparticles and at the same time summarize some recent works carried out in the synthesis of organic and inorganic nanoparticles by this method.
Journal ArticleDOI
Microemulsion dynamics and reactions in microemulsions
TL;DR: The use of micro-emulsions for the preparation of nanoparticles has been studied in this paper, where the authors present a review of the recent tendencies of the use of such reaction media for nanoparticles and particularly interesting organic reaction media.
References
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Monodisperse FePt Nanoparticles and Ferromagnetic FePt Nanocrystal Superlattices
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Surface Plasmon Spectroscopy of Nanosized Metal Particles
TL;DR: In this paper, the use of optical measurements to monitor electrochemical changes on the surface of nanosized metal particles is discussed within the Drude model, and the absorption spectrum of a metal sol in water is shown to be strongly affected by cathodic or anodic polarization, chemisorption, metal adatom deposition, and alloying.
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Alloy Formation of Gold−Silver Nanoparticles and the Dependence of the Plasmon Absorption on Their Composition
TL;DR: In this article, a co-reduction of chlorauric acid HAuCl4 and silver nitrate AgNO3 with sodium citrate is used to form homogeneous gold−silver alloy nanoparticles.
Journal ArticleDOI
Nucleation and Growth of CdSe on ZnS Quantum Crystallite Seeds and Vice Versa, in Inverse Micelle Media
A. R. Kortan,Robert Hull,Robert L. Opila,Moungi G. Bawendi,Michael L. Steigerwald,P. J. Carroll,Louis E. Brus +6 more
TL;DR: In this article, a simple theoretical model for the LUMO and HOMO of layered crystallites is presented, showing that a small (< 15-angstrom) diameter interior foreign seed causes only small shifts of the lowest excited state, to either higher or lower energies.
Journal ArticleDOI
In situ synthesis of silver nanocluster in AOT reverse micelles
TL;DR: In this paper, a functionalized surfactant, silver sulfosuccinate (Ag(AOT)), a reactant, was used to obtain a high concentration of monodisperse and stable nanosize particles even in the presence of air.