Nonaqueous perfluorocarbon-derived gold colloids. 1. Clustering of metal atoms in fluorocarbon media

Zuckerman, Ellis B.; Klabunde, Kenneth J.; Olivier, Bernard J.; Sorensen, Christopher M.

doi:10.1021/cm00001a006

Cited by 26 publications

(13 citation statements)

References 1 publication

(2 reference statements)

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“…When this frozen metal/organic mixture is allowed to warm, nucleation and growth take place and a colloidal dispersion of the metal was then obtained after melting. SMAD can be used to prepare supported Au catalyst simply by mixing SMAD with solid support and in such a way Au particles of 2 to 15 nm are deposited on oxide and polymers [59][60][61][62][63]. As in the case of Magnetron sputtered catalyst, AuNPs can be considered as "naked" NPs because no strong coordinating ligands are present.…”

Section: Metal Vapor Depositionmentioning

confidence: 99%

The Art of Manufacturing Gold Catalysts

Prati

Villa

2011

Catalysts

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Section: Metal Vapor Depositionmentioning

confidence: 99%

The Art of Manufacturing Gold Catalysts

Prati

Villa

2011

Catalysts

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“…Since then, the preoccupation with these systems has progressively escalated, fueled primarily by their fascinating properties (especially optical) and their potential for new applications in catalysis [2][3][4][5][6], nonlinear optics [5,[7][8][9][10], electronics [11][12][13], pigments [14,15], biology [16][17][18][19][20], sensors [21], biosensors [22] dentistry, heat reflecting coatings, and other domains of high technology and medicine [23,24]. Since Faraday's pioneering work, many different routes to produce colloidal gold have been reported, including the condensation of metal vapors in solvents [25][26][27][28], in polymers [29] or other matrices, as well as the thermal decomposition of precursor metallic compounds suspended in either liquids [30] or gas streams (aerosol thermolysis). The vast majority of the processes, however, involve the reduction of gold compounds in solutions.…”

Section: Introductionmentioning

confidence: 99%

Stabilizer-free nanosized gold sols

Andreescu

Goia

2006

Journal of Colloid and Interface Science

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“…Cryoparticles of zinc were prepared by means of a low temperature technique (Solvated Metal Atom Dispersion = SMAD) (Klabunde, 1994) involving codeposition of metal and organic solvent (pentane, toluene) vapors on a reactor wall at 77 K, followed by warming to room temperature and solvent evaporation. Cryoparticles were placed under vacuum overnight to diminish the amount of organic species that could be associated with surface metal atoms (Davis, Severson, and Klabunde, 1981;Zuckerman et al, 1989). Nevertheless, elemental analysis performed by Desert Analytics (Tuscon, Arizona) indicated higher carbon and hydrogen content for zinc cryo particles 0.85-1.11% and 0.10-0.12%, respectively, compared to 0.07 and 0.02% for Zn dust.…”

Section: Chemicalsmentioning

confidence: 99%

“…Mechanical activation (crushing or grinding) of zinc caused a noticeable increase in methane production (Boronina et al, submitted). Use of nanoscale metal particles, possessing both large surface area and high surface active sites concentration (Klabunde, 1994;Davis, Severson, and Klabunde, 1981;Zuckerman et al, 1989) has given 2-3 fold increase in dechlorination rate and methane production (Boronia, Klabunde, and Sergeev, 1995;Boronina and Klabunde, 1996;Burris, Campbell, and Manoranjan, 1995;Wang and Zhang, 1997).…”

Section: Introductionmentioning

confidence: 99%

Zinc-Silver, Zinc-Palladium, and Zinc-Gold as Bimetallic Systems for Carbon Tetrachloride Dechlorination in Water

Boronina¹,

Dieken²,

Lagadic³

et al. 1998

Journal of Hazardous Substance Research

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Doping of zinc with silver, palladium, and gold was found to increase reactivity towards carbon tetrachloride in water. Commercial zinc dust, cryochemically prepared zinc metal particles (SMAD nanoparticles), and zinc dust pressed into pellets (mechanically activated zinc) were employed. Reduction products detected were methane, ethylene, acetylene, and other hydrocarbons along with products of partial dechlorination such as chloroform, methylene chloride, and methyl chloride. Dichloroethylenes (DCEs) and long-term reactions traces of trichloroethylene (TCE) were also detected. The use of zinc dust doped with palladium, gold, and silver resulted in 4-10 fold increases in carbon tetrachloride degradation rate and conversion into methane. Up to 30 % of carbon tetrachloride was converted into methane by the Zn dust / 2 mol % Ag bimetallic system after the first six hours of reaction. Doping of activated forms of zinc, both cryoparticle and pellets, caused a further increase in methane formation and decrease in the concentration of methylene chloride. The data show that bimetallic enhancement with Pd, Ag, Au, as well as cryo and mechanical activation of zinc, enhances the metal surface reactivity and changes the priority of reaction pathways such that fully reduced products are favored. The non-catalytic gold metal was especially effective and this suggests that electron transfer, not catalytic hydrogenation, is rate determining.Key words: zinc, bimetallic, silver, palladium, gold, carbon tetrachloride, echlorination, water INTRODUCTIONUse of zero-valent metals, in particular iron, for reduction in water of chlorinated solvents, such as carbon tetrachloride (CT), trichloroethylene (TCE), and tetrachloroethylene (PCE), has been an area of significant interest, as the prospects for field application look quite promising (Appleton, 1996; Orth and Gillham, 1994;Matheson and Tratnyek, 1994;Starr and Cherry, 1994). Nevertheless, implementation of zero-valent iron technology still faces several problems. One of them is the production and accumulation of chlorinated products due to the low reactivity of iron towards lightly chlorinated hydrocarbons. Dechlorination of CT by iron was shown to produce persistent methylene chloride (Johnson, Scherer, and Tratnyek, 1996;Matheson and Tratnyek, 1994). Products of perchloroethylene (PCE) and trichloroethylene (TCE) dechlorination, 1,2 -dichloroethylenes (DCEs), and vinyl chloride (VC) react only slowly with iron (Orth and Gillham, 1994;Hardy and Gillham, 1996;Roberts et al., 1996) and results are only marginally better in the presence of zinc Roberts et al., 1996). On the other hand, zinc converts chlorinated methanes into gaseous methyl chloride and methane, though methylene chloride degradation is still about two orders in magnitude slower than CT under the same experimental conditions . (We speculate that the relatively low reactivity with methylene chloride, DCE, and VC is due to the lessened electron demand due to fewer chlorines, thereby electron transfer from the metals...

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Nonaqueous perfluorocarbon-derived gold colloids. 1. Clustering of metal atoms in fluorocarbon media

Cited by 26 publications

References 1 publication

The Art of Manufacturing Gold Catalysts

The Art of Manufacturing Gold Catalysts

Stabilizer-free nanosized gold sols

Zinc-Silver, Zinc-Palladium, and Zinc-Gold as Bimetallic Systems for Carbon Tetrachloride Dechlorination in Water

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