Nucleation and initial growth of platinum islands by plasma sputter deposition

Andreazza, Pascal; Andreazza‐Vignolle, C.; Rozenbaum, J.P.; Thomann, Anne-Lise; Brault, Pascal

doi:10.1016/s0257-8972(01)01604-8

Cited by 48 publications

(41 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As growth proceeds, islands coalesce and enlarge and there is a decrease in island density (Figure 5b). Finally the islands increase in size by branching with other meandering islands until a percolation network of Pt forms [36] as is seen for 9 s (Figure 5c). …”

Section: Oil Analysissupporting

confidence: 56%

“…The Pt loading at this stage is 3.4 μg cm -2 with about 72 area% of the polymer surface covered with Pt. Figure 5 seems to indicate growth of Pt islands according to the Volmer-Weber mechanism [36]. In this mechanism during the first growth stage, metal nucleation occurs and metal clusters grow in diameter and there is an increase in the metal islands density.…”

Section: Oil Analysismentioning

confidence: 96%

See 1 more Smart Citation

Partial hydrogenation of soybean oil using metal-decorated integral-asymmetric polymer membranes: Effects of morphology and membrane properties

Singh

Rezac

Pfromm

2010

Journal of Membrane Science

View full text Add to dashboard Cite

Three phase reaction schemes pose numerous challenges to reactor design due to the slow diffusional mass transfer of reactants from the gas phase through a liquid to the active sites of the catalyst. An example is partial hydrogenation of vegetable oil which is traditionally carried out in a batch autoclave by bubbling hydrogen gas though a slurry of oil and solid catalyst particles containing Ni. Unwanted trans fatty acids (TFA) are formed during this process due to the scarcity of hydrogen at the active catalyst sites. Here we investigate the use of metal decorated integral-asymmetric polymer membranes to enable the supply of dissolved hydrogen near the location where the liquid oil phase contacts the catalyst. Hydrogen gas is supplied to the porous sub-structure of the asymmetric membrane where it dissolves in the thin skin layer of the membrane and emerges as dissolved hydrogen on the metal-decorated side of the membrane where the oil is present. Temperature and pressure are compatible with existing facilities. All membranes produced low TFA (2.6-4.6 wt% at Iodine Value of 95) compared to the slurry process. A 1000 metric ton per day soybean oil hydrogenation facility would require 2-3000 m 2 membrane area with a total of 90 grams of Pt metal catalyst. This could be envisioned as metal sputtered hollow fibers packaged in conventional modules.

show abstract

Section: Oil Analysissupporting

confidence: 56%

Section: Oil Analysismentioning

confidence: 96%

Partial hydrogenation of soybean oil using metal-decorated integral-asymmetric polymer membranes: Effects of morphology and membrane properties

Singh

Rezac

Pfromm

2010

Journal of Membrane Science

View full text Add to dashboard Cite

show abstract

“…The study of initial electrocrystalization of metals is an important area of study [7][8][9][10]. A number of studies have been reported for the investigation of the initial nucleation of cobalt [32], copper [14,22,25,27,29,33], palladium [7, 13, 16-19, 21, 23, 34, 36], platinum [20,28] and silver [31] on various substrates. Initial electro-nucleation studies are important as it provides a mechanistic study with simple approach that can be used to approximate the actual initial nucleation without the help of expensive instruments such as atomic force microscopy and other nano-imaging tools.…”

Section: Introductionmentioning

confidence: 99%

Tuning the Initial Electronucleation Mechanism of Palladium on Glassy Carbon Electrode

Alemu¹,

Assresahegn²,

Soreta³

2014

Port. Electrochim. Acta

View full text Add to dashboard Cite

Electrochemical metal nucleation is the method for the formation of metal nanoparticles on the electrode surface. Studying the early stage of electronucleation is simpler than other methods as the driving force for nucleation is achieved by changing deposition potentials and concentration of metal ions. In this work, the potential step electrochemical deposition of palladium was studied from its chloride solution at room temperature on glassy carbon electrode surface. The nucleation mechanism was studied by analysis of the resulting current transients. Accordingly, the initial electro-nucleation mechanism of palladium nanoparticles was found to be varying depending on deposition conditions such as deposition potential and palladium concentration. It can be changed from 3D instantaneous (for all deposition potentials studied and in higher electrolytic concentration) to 3D progressive nucleation mechanism (for lower deposition potential and lower electrolytic concentration). In addition, the nucleation rate for each deposition potential as well as the concentration has been determined. The nucleation rate in this research is used to calculate the nuclei density and found to decrease from more negative deposition potential to more positive deposition potential in agreement with the observed shift in electronucleation mechanism.

show abstract

“…During deposition, Pt atoms also diffuse in the porous layer [3,10]. The resulting platinum depth profiles were measured using RBS [9].…”

Section: Characterizations Of Catalystsmentioning

confidence: 99%

“…This deposition technique is largely used by industry and for R&D on fuel cells [1,2]. It has the advantage of allowing the deposition of very small quantities of material and the optimisation of its nanostructure [3,4]. The first part of the presentation will be devoted to the experimental development for Pt deposition on a gas diffusion layer and to the physicochemical deposition of the catalytic material.…”

Section: -Introductionmentioning

confidence: 99%

High Performance Plasma Sputtered Fuel Cell Electrodes with Ultra Low Catalytic Metal Loadings

Coutanceau¹,

Brault²,

Caillard³

et al. 2011

ECS Trans.

View full text Add to dashboard Cite

Ultra-low Pt content PEMFC electrodes have been manufactured using magnetron co-sputtering of carbon and platinum on a commercial E-Tek uncatalyzed gas diffusion layer in plasma fuel cell deposition devices. Pt loadings lower than 0.01 mg cm-2 have been realized. The Pt catalyst is dispersed as small clusters with size less than 2 nm over a depth of 500 nm. PEMFC test with symmetric electrodes loaded with 0.01 mg cm-2 led to maximum reproducible power densities as high as 0.4 Wcm-2 with Nafion 212. Replacement of platinum by palladium using plasma sputtering methods was also realized by preparing MEAs composed of 0.01 mgPd cm-2 for the anode and 0.01 mgPd cm-2 + 0.001 mgPt cm-2 for the cathode and Nafion 212 membrane. Power density as high as 250 mW cm-2 were achieved at 80°C, which corresponds to a specific power density of 250 kW gPt-1.

show abstract

Nucleation and initial growth of platinum islands by plasma sputter deposition

Cited by 48 publications

References 18 publications

Partial hydrogenation of soybean oil using metal-decorated integral-asymmetric polymer membranes: Effects of morphology and membrane properties

Partial hydrogenation of soybean oil using metal-decorated integral-asymmetric polymer membranes: Effects of morphology and membrane properties

Tuning the Initial Electronucleation Mechanism of Palladium on Glassy Carbon Electrode

High Performance Plasma Sputtered Fuel Cell Electrodes with Ultra Low Catalytic Metal Loadings

Contact Info

Product

Resources

About