One‐Pot Synthesis of Core‐Shell Silver‐Gold Nanoparticle Solutions and Their Interaction with Methylene Blue Dye

Abstract

A one-pot modified Turkevich synthesis was used to synthesise a range of colloids from pure Ag, through Ag/Au coreshell mixtures to pure Au by the thermal co-addition of trisodium citrate to auric acid and silver nitrate mixtures. The colloids were analysed by means of XRD and wide-beam energy dispersive X-ray (EDX) analysis. The UV/Vis spectroscopy showed a non-linear variation in the surface plasmon resonance band with the Au/Ag ratio, consistent with core-shell formation. High resolution transmission electron microscopy (HRTEM) imaging, in conjunction with thinbeam EDX line analysis, confirmed the presence of predominantly Ag cores and Au exteriors in the Au/Ag mixture. The argon ion sputtering with X-ray photoelectron spectroscopy (XPS) measurements of the particles also indicated a Ag-Au

Selective and sensitive colorimetric determination of cobalt ions using Ag–Au bimetallic nanoparticles

“…Distribution of Ag and Au elements in BNPs proved that the nanoparticles consist of a predominant Ag core and a Au rich shell, which is consistent with the reported structure. 17 As shown in Fig. 1E, the valence of both Ag and Au in BNP XPS was zero due to the overdose of the reducing agent.…”

“…Ag-Au BNPs were prepared according to the previous reported papers with slight modications. 17 In brief, 182 mL 0.1 M AgNO 3 and 250 mL 24.28 mM (1% in weight) HAuCl 4 solutions was added into 95.5 mL distilled water in a ask. The mixture was heated to boil in oil bath under constant stirring at 250 rpm.…”

“…We prepared Ag-Au BNPs by a one-pot synthetic procedure. 38,39 According to the literature, 17 the BNPs have Ag core-Au shell structures, which endows them high stability. The molar ratio of Ag : Au was nally set to be 3 : 1, since the compromise was made between the strong optical properties of nanoparticles relating to the detection signals and the well chemical stability associating with convenient storage.…”

“…16 The bands of localized surface plasmonic resonance in the range of 400-550 nm can be conveniently tuned by varying their components while keeping the nanoparticle diameter constant. 17 Correspondingly, the BNP solution color could also vary from yellow to brown, to red by changing the components. Thus, BNP-based probes can provide low detection background, well stability and high sensitivity in assays.…”

Thermoplasmonics-assisted nanoheterostructured Au-decorated CuInS2 nanoparticles: Matching solar spectrum absorption and its application on selective distillation of non-polar solvent systems by thermal solar energy

“…To tackle and broaden absorption ranges of NPs, hybrid NPs such as Fe 3 O 4 /Au, [9] SiO 2 /Fe 2 O 3 -Au, [10] Au/TiO 2 , [11] Au/Pd, [12] SiO 2 /Au, [13][14][15][16] Graphene/Au, [17] Ag/Au, [18] SiO 2 /Ag [19] and VO 2 /Au [20] have been proposed, which provide advantages of equivalent light absorption by an increase of absorption cross-section compared with the counterpart materials NPs, thereby consuming less volume of metal NPs. In addition, superimposing functionalities such as magnetic and optical dual properties can be contributed from hybrid NPs for possible applications at bio-imaging, [9] thermal ablation of bacterium [9] and ambient oxygen-free dehydrogenation of aromatic alcohols by catalytic-thermal plasmonic effect [12].…”