Continuous flow and flow injection potentiometry of complex-bonded metal ions by the standard additions method

Rizov, Ivelin; Ilcheva, Liliana

doi:10.1039/an9952001651

Cited by 5 publications

(2 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results obtained using tetrahedral and cubic nanoparticles show that the presence of thiosulfate ions does not change the shape distribution of the nanoparticles. The observations found in both the tetrahedral and cubic shaped nanoparticles is consistent with what is well-known in the literature − that thiosulfate binds to metal surfaces such as silver, cadmium, palladium, nickel, aluminum, zinc, platinum, etc. through its sulfur group.…”

Section: Resultssupporting

confidence: 91%

Effect of Nanocatalysis in Colloidal Solution on the Tetrahedral and Cubic Nanoparticle SHAPE: Electron-Transfer Reaction Catalyzed by Platinum Nanoparticles

2004

View full text Add to dashboard Cite

The stability of tetrahedral and cubic platinum nanoparticles during the catalysis of the electron-transfer reaction between hexacyanoferrate (III) and thiosulfate ions in colloidal solution at room temperature was studied by using TEM and HRTEM. Before the reaction, the dominantly tetrahedral nanoparticles have a shape distribution of 55 ( 4% regular tetrahedral, 22 ( 2% distorted tetrahedral, and 23 ( 2% spherical nanoparticles, and the dominantly cubic nanoparticles have an initial shape distribution of 56 ( 4% regular cubes, 13 ( 1% distorted cubes, and 31 ( 3% truncated octahedral nanoparticles. The amount of tetrahedral nanoparticles decreases by 60 ( 5% after the first cycle and by 62 ( 4% after the second cycle of the reaction. In the case of cubic nanoparticles, the amount of cubic nanoparticles decreases by 39 ( 5% after the first cycle and by 66 ( 5% after the second cycle compared to before the reaction. After the first and second cycles of the reaction, there are a greater percentage of distorted tetrahedral and distorted cubic nanoparticles present. The rate of the dissolution of the surface Pt atoms is faster for the tetrahedral nanoparticles than for the cubic nanoparticles. This suggests that tetrahedral nanoparticles, with their sharp corners and edges, are more sensitive and more liable to shape changes during nanocatalysis. The presence of just hexacyanoferrate ions in the solution with the nanoparticles is found to increase the amount of distorted tetrahedral and distorted cubes present much more than during the reaction. The presence of only the thiosulfate ions does not seem to affect the size or shape distribution which might result from the capping ability of this anion and thus protects the nanoparticles.

show abstract

Section: Resultssupporting

confidence: 91%

Effect of Nanocatalysis in Colloidal Solution on the Tetrahedral and Cubic Nanoparticle SHAPE: Electron-Transfer Reaction Catalyzed by Platinum Nanoparticles

2004

View full text Add to dashboard Cite

show abstract

“…The reason the nanoparticles maintain their stability in the presence of the thiosulfate ions might be that the thiosulfate ions bind to the free sites on the nanoparticle surface and act as a capping material. It is well-known in the literature − that thiosulfate binds to metal surfaces such as silver, cadmium, palladium, nickel, aluminum, zinc, platinum, etc. As a result, it is very logical to propose that the thiosulfate is binding to the free sites of the PVP−Pt nanoparticle surface.…”

Section: Resultsmentioning

confidence: 99%

Effect of Catalytic Activity on the Metallic Nanoparticle Size Distribution: Electron-Transfer Reaction between Fe(CN)₆and Thiosulfate Ions Catalyzed by PVP−Platinum Nanoparticles

2003

View full text Add to dashboard Cite

The electron-transfer reaction between hexacyanoferrate(III) ions and thiosulfate ions is known to be catalyzed by platinum nanoparticles. In the present study, the stability and catalytic activity of the PVP−Pt nanoparticle during its catalytic function for this electron-transfer reaction is studied. The stability of the nanoparticles after various perturbations was assessed using TEM, and the kinetics of the reaction was followed using absorption spectroscopy. The studies were conducted on four different concentrations of PVP−Pt nanoparticles. It was found that the average size and width of the PVP−Pt nanoparticles decrease slightly after the first and second cycles of the electron-transfer reaction. The size and size distribution width do not change in the presence of only the thiosulfate reactant, whereas the presence of only the hexacyanoferrate reactant results in a reduction of the nanoparticle size. The reduction in the nanoparticle size in the presence of hexacyanoferrate(III) ions is proposed to result from the dissolution of surface Pt atoms through complexation with the strong cyanide ligand. Thiosulfate ions bind to the nanoparticle surface and act as a capping material, resulting in the stability of the nanoparticles. Judging from these observations, it is possible that the mechanism of this catalytic reaction involves the thiosulfate ions binding to the free sites on the surface of the nanoparticles, followed by reaction with hexacyanoferrate ions approaching the nanoparticle surface from the solution. Conducting the reaction with the nanoparticles preexposed to thiosulfate results in very little change in the centers and widths of the size distributions of the nanoparticles, thus suggesting that thiosulfate ions bind to the nanoparticle surface and inhibit desorption of Pt atoms by hexacyanoferrate(III) ions. The kinetics of the electron-transfer reaction during the first and second cycles is similar. The activation energy of the nanoparticle catalytic reaction is found to decrease linearly with increasing nanoparticle concentration during both the first and second cycles. If increasing the nanoparticle concentration leads to more aggregation, then these results suggest that the aggregated Pt has greater catalytic activity than the individual nanoparticles.

show abstract

Sequential injection analysis using electrochemical detection: A review

Pérez-Olmos

Soto

Zárate

et al. 2005

Analytica Chimica Acta

View full text Add to dashboard Cite

Continuous flow and flow injection potentiometry of complex-bonded metal ions by the standard additions method

Cited by 5 publications

References 17 publications

Effect of Nanocatalysis in Colloidal Solution on the Tetrahedral and Cubic Nanoparticle SHAPE: Electron-Transfer Reaction Catalyzed by Platinum Nanoparticles

Effect of Nanocatalysis in Colloidal Solution on the Tetrahedral and Cubic Nanoparticle SHAPE: Electron-Transfer Reaction Catalyzed by Platinum Nanoparticles

Effect of Catalytic Activity on the Metallic Nanoparticle Size Distribution: Electron-Transfer Reaction between Fe(CN)₆and Thiosulfate Ions Catalyzed by PVP−Platinum Nanoparticles

Sequential injection analysis using electrochemical detection: A review

Contact Info

Product

Resources

About

Continuous flow and flow injection potentiometry of complex-bonded metal ions by the standard additions method

Cited by 5 publications

References 17 publications

Effect of Nanocatalysis in Colloidal Solution on the Tetrahedral and Cubic Nanoparticle SHAPE: Electron-Transfer Reaction Catalyzed by Platinum Nanoparticles

Effect of Nanocatalysis in Colloidal Solution on the Tetrahedral and Cubic Nanoparticle SHAPE: Electron-Transfer Reaction Catalyzed by Platinum Nanoparticles

Effect of Catalytic Activity on the Metallic Nanoparticle Size Distribution: Electron-Transfer Reaction between Fe(CN)6and Thiosulfate Ions Catalyzed by PVP−Platinum Nanoparticles

Sequential injection analysis using electrochemical detection: A review

Contact Info

Product

Resources

About

Effect of Catalytic Activity on the Metallic Nanoparticle Size Distribution: Electron-Transfer Reaction between Fe(CN)₆and Thiosulfate Ions Catalyzed by PVP−Platinum Nanoparticles