title: Green synthesis and applications of Au-Ag bimetallic nanoparticles.
abstract: This paper reports for the first time the synthesis of bimetallic nanoparticles at room temperature using the fruit juice of pomegranate. Simultaneous reduction of gold and silver ions in different molar ratios leads to the formation of alloy as well as core-shell nanostructures. The nanoparticles have been characterized using UV-vis spectroscopy, transmission electron microscopy, Fourier Transform Infrared Spectroscopy and X-ray diffraction. The synthesized alloy particles are used as catalysts in the reduction of 2-, 3-, 4-nitrophenols to the corresponding amines and in the degradation of methyl orange. The reduction kinetics for all the reactions follows pseudo-first order. The rate constants follow the order k4-nitrophenol<k2-nitrophenol<k3-nitrophenol. Thermal conductivity is measured as a function of volume fraction and it is observed that the incorporation of the alloy nanoparticles enhances the thermal conductivity of the base fluid (water) showing nanofluid application. The nitric oxide and hydroxyl radical scavenging activity shown by the nanoparticles promise the potential application in biomedical field.
authors.affiliation: Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, India.
authors.forename: M
authors.initials: M
authors.lastname: Meena Kumari
authors.affiliation: Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, India.
authors.forename: John
authors.initials: J
authors.lastname: Jacob
authors.affiliation: Department of Physics, Mar Ivanios College, Thiruvananthapuram 695 015, India. Electronic address: daizyp@rediffmail.com.
authors.forename: Daizy
authors.initials: D
authors.lastname: Philip
mesh_terms: D065966:Absorption, Physicochemical; D000975:Antioxidants / Q000494:pharmacology; D002384:Catalysis; D003102:Colloids; D016166:Free Radical Scavengers / Q000494:pharmacology; D006046:Gold / Q000737:chemistry*; D055772:Green Chemistry Technology / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D055620:Optical Phenomena; D012834:Silver / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D000975:Antioxidants; D003102:Colloids; D016166:Free Radical Scavengers; D012834:Silver; D006046:Gold
keywords: Antioxidant activity; Au–Ag alloy nanoparticles; Au–Ag core–shell nanoparticles; Catalysis; Nanofluid; Thermal conductivity