Radiation-electrochemistry of the colloidal platinum microelectrode

Henglein, A.; Lindig, Barbara A.; Westerhausen, J.

doi:10.1016/0146-5724(84)90109-2

Cited by 3 publications

(3 citation statements)

References 13 publications

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“…Since the reduction is performed under air, the presence of dissolved oxygen is expected to lead to formation of PtO x phases at the surface of the metallic particles. 26,33 Superficial platinum oxide phases have been in fact detected by time-of-flight secondary ion mass spectrometry (TOF-SIMS) in a previous analysis of the platinum powders obtained following a reduction protocol analogous to the one used in this work. 34 Furthermore, an XPS analysis of the same material confirmed the metallic character of the obtained particles, revealing the presence of oxygen and carbon adsorbates, together with chlorine and potassium ions.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Platinum Cluster Chains on DNA Templates: Conditions for a Template-Controlled Cluster Growth

et al. 2004

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We investigate the conditions which should be fulfilled to grow chains of nanosized noble metal clusters on DNA templates according to a selectively heterogeneous, template-controlled mechanism. A long incubation of double-stranded DNA molecules with Pt(II) complexes is necessary to obtain a template-directed formation of thin and uniform cluster chains after chemical reduction of the DNA/salt solution. Without this “activation” step, DNA acts as a nonspecific capping agent for the formed clusters and does not hinder the formation of random cluster aggregates. The effect of binding Pt(II) complexes to the DNA is investigated by UV−vis spectroscopy, electrophoresis experiments, and scanning force microscopy, revealing that the base stacking along the DNA molecule is significantly distorted but the double-stranded DNA configuration is retained. Citrate ions can be used as additional stabilizers for the heterogeneously grown metal clusters, leading to significantly more regular metal cluster chains. After a systematic variation of the absolute concentration of the reactants (Pt salt, DNA, reducing agent), we can conclude that there is an optimum concentration value for the fabrication of cluster chains and that small variations around the optimum value do not have noticeable effects on the quality of the metallization products. The described metallization procedure can be resolved into a series of simple and efficient steps, which is essential for a biomimetic fabrication of nanostructures in a reproducible way.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Platinum Cluster Chains on DNA Templates: Conditions for a Template-Controlled Cluster Growth

et al. 2004

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“…This manifests itself in the destabilization they undergo upon exposure to hydrogen gas and the formation of colored Chini complexes upon the exposure to CO . Studies on the interaction of these particles with reducing free radicals have also shown that some kind of higher oxidation state is present …”

Section: Introductionmentioning

confidence: 99%

“…This manifests itself in the destabilization they undergo upon exposure to hydrogen gas and the formation of colored Chini complexes upon the exposure to CO. 5 Studies on the interaction of these particles with reducing free radicals have also shown that some kind of higher oxidation state is present. 6 In the present work, some features of the H 2 reduction of Pt(II) are investigated, and the nature of the nanoparticles formed is studied by electron microscopy. It was found that the reduction by H 2 at ambient temperature in the presence of sodium citrate yields Pt sols of particularly long lifetime.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Pt(II) by H₂: Effects of Citrate and NaOH and Reaction Mechanism

2000

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Aqueous solutions of Pt(II) (aged PtCl4 2- solutions) are reduced by hydrogen in the absence of a stabilizer and in the presence of stabilizing sodium citrate or/and sodium hydroxide. The rate of reduction is measured optically and conductometrically, and the colloidal nanoparticles, which are finally formed, are studied by high-resolution electron microscopy. In dilute solutions, the rate of reduction is proportional to the square of the Pt(II) concentration. In the presence of citrate and NaOH, the reduction occurs more slowly. A mechanism, in which intermediate free Pt atoms do not appear, is discussed. Monovalent platinum is postulated as the first intermediate, and an autocatalytic contribution to the reduction is observed. Particle growth in a chain reaction is also discussed. In the presence of NaOH, the reaction occurs in two steps: formation of a hydroxilated precursor and reduction of the latter. Depending on the concentration of the stabilizing additives, colloids consisting of polyhedra of different shape (cubic, tetrahedral, and triculent octahedral) are formed. Stabilization by citrate plus NaOH yields particularly long lifetimes of the colloidal solutions.

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Mechanism of reactions on colloidal microelectrodes and size quantization effects

Henglein¹

Topics in Current Chemistry

507

121

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Radiation-electrochemistry of the colloidal platinum microelectrode

Cited by 3 publications

References 13 publications

Synthesis of Platinum Cluster Chains on DNA Templates: Conditions for a Template-Controlled Cluster Growth

Synthesis of Platinum Cluster Chains on DNA Templates: Conditions for a Template-Controlled Cluster Growth

Reduction of Pt(II) by H₂: Effects of Citrate and NaOH and Reaction Mechanism

Mechanism of reactions on colloidal microelectrodes and size quantization effects

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Radiation-electrochemistry of the colloidal platinum microelectrode

Cited by 3 publications

References 13 publications

Synthesis of Platinum Cluster Chains on DNA Templates: Conditions for a Template-Controlled Cluster Growth

Synthesis of Platinum Cluster Chains on DNA Templates: Conditions for a Template-Controlled Cluster Growth

Reduction of Pt(II) by H2: Effects of Citrate and NaOH and Reaction Mechanism

Mechanism of reactions on colloidal microelectrodes and size quantization effects

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Reduction of Pt(II) by H₂: Effects of Citrate and NaOH and Reaction Mechanism