Composite Pd-Ag Particles in Aqueous Solution

Michaelis, M.; Henglein, A.; Mulvaney, Paul

doi:10.1021/j100075a025

Cited by 98 publications

(65 citation statements)

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“…Gold clusters absorb in the visible with a maximum at around 510-520 nm. The maximum of the UV plasmon band of palladium clusters has been calculated ranging around 205-220 nm, 12 from the bulk dielectric data. 28 For making possible the comparison with the mixed solutions, monometallic solutions of Pd II or Au III were first irradiated 7,8,29 under the same conditions.…”

Section: Resultsmentioning

confidence: 99%

Dose Rate Effect on Bimetallic Gold−Palladium Cluster Structure

2002

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Radiolytic synthesis of mixed Au III /Pd II solutions at different dose rates is examined. The evolution of the plasmon spectra and the local X-ray micro diffraction has been systematically studied as a function of irradiation dose and dose rate. At low dose rate, a bilayered cluster of Au core-Pd shell is characterized. Due to intermetal electron transfer from nascent Pd atoms to gold ions, the latter are reduced first and constitute mainly the core of the particle, Pd ions being finally reduced at the surface of gold clusters when all Au III ions have been reduced. In contrast, at high dose rate when the ion reduction is sudden and faster than a possible inter-metal electron transfer, it is shown by UV-vis spectroscopy, XPS, and EDAX results that genuine alloyed clusters are formed.

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Section: Resultsmentioning

confidence: 99%

Dose Rate Effect on Bimetallic Gold−Palladium Cluster Structure

2002

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“…[16] However, we still do not understand the actual clustering process. What governs the kinetics of cluster formation in solution?…”

Section: Introductionmentioning

confidence: 99%

In Situ Spectroscopic Analysis of Nanocluster Formation

et al. 2004

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The importance of small metal clusters in catalysis and the problems in understanding the clustering process in solution are outlined. A new analysis method for UV/Vis spectra is presented and applied to monitor the kinetics of ion reduction and cluster formation in situ. This method, which is based on a combination of two chemometric techniques, takes into account the entire UV/Vis spectrum and offers better interpretation possibilities than the traditional "band-assignment" approach. This is particularly true for nanoclusters because these have significant spectral contributions also outside the broad plasmon band that is usually associated with them. The reduction of palladium, gold, and silver ions and the formation of the corresponding clusters is monitored in the presence of two different reducing agents, sodium borohydride and tetraoctylammonium acetate. While Pd2+ is found to reduce and cluster directly, the spectral decomposition of the Au3+ reduction profiles shows two species corresponding to the Au+ intermediate and the Au0 clusters. The rates of reduction and clustering for Pd, Au, and Ag are compared and the possibilities of synthesising multimetallic clusters of these metals by coreduction are discussed.

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“…21) Henglein adopted the radiation-reduction method to achieve bimetallic nanoparticles with a palladium core and a silver shell. 22) Tseng employed electrical discharge machining (EDM) and the submerged arc discharge method (SADM) to melt conductive metals into various types of nanometal colloids through concentrated arc energy (e.g., nanosilver, 23) nanogold, 24) nanocopper, 25) and nanoaluminum, 26) and to explore the relationships between the characteristics of silver, copper, and titanium nanofluids and the EDM process parameters. 27) In this study, the SADM was employed to produce nanosilver-copper composite metal fluids (i.e., the positive electrode of a metal rod was silver, and the negative electrode was copper; both electrodes were submerged in dielectric fluid).…”

Section: Introductionmentioning

confidence: 99%

Preparation of Ag-Cu Composite Nanoparticles by the Submerged Arc Discharge Method in Aqueous Media

et al. 2016

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For this study, electrical discharge machining (EDM) and the submerged arc discharge method (SADM) were used to melt a silver-copper composite metal in deionized water through concentrated arc energy in order to produce metal fluids containing nano-and submicron particles. The fabrication process did not require additional chemicals, and was simple and efficient. The critical processing parameters for EDM were the discharge voltage and current as well as the on-off duration for pulse discharge; the sample concentration could be controlled under appropriate conditions. The experimental results revealed that, through electronic system design and manufacturing (ESDM), silver-copper composite metal particles could be achieved at a nano to submicron level. In addition, the results obtained varied according to differences in the on-off duration regarding pulse discharge. In this study, when the discharging parameter (T on -T off ) was at 30 : 50, nanocomposite fluids with an optimal concentration and small particles were obtained. The application of EADM could enable the mass production of composite metal fluids or particles at low cost and high efficiency. Employing EADM for the fabrication of composite metal fluids or particles warrants research attention, and the process itself can be developed further.

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Composite Pd-Ag Particles in Aqueous Solution

Cited by 98 publications

References 0 publications

Dose Rate Effect on Bimetallic Gold−Palladium Cluster Structure

Dose Rate Effect on Bimetallic Gold−Palladium Cluster Structure

In Situ Spectroscopic Analysis of Nanocluster Formation

Preparation of Ag-Cu Composite Nanoparticles by the Submerged Arc Discharge Method in Aqueous Media

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