Electrochemical Preparation of Platinum Nanocrystallites with Size Selectivity on Basal Plane Oriented Graphite Surfaces

Zoval, Jim; Lee, J.; Gorer, S.; Penner, Reginald M.

doi:10.1021/jp9731967

Cited by 309 publications

(366 citation statements)

References 37 publications

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“…Noncontact atomic force microscope (NC-AFM) images of a graphite surface following the deposition of 0.039 monolayer of platinum, for example, are shown in Figure 2a. 19 Platinum nanoparticles having a mean diameter of 52 Å are seen on a graphite surface in this image. The image of Figure 2a also shows that platinum nanoparticles have nucleated both at defect sites such as step edges, and on atomically smooth terraces.…”

Section: Electrodeposition Of Size-monodisperse Metal Nanoparticlesmentioning

confidence: 78%

Hybrid Electrochemical/Chemical Synthesis of Quantum Dots

Penner

2000

Acc. Chem. Res.

115

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The "electrochemical/chemical method" (or "E/C method") is a new wet chemical method for synthesizing semiconductor quantum dots on graphite surfaces. The E/C synthesis of quantum dots composed of the generic semiconducting salt, MX, typically involves three steps: (1) electrochemical deposition of nanoparticles of the metal, M°, from a solution of metal ions, M n+ ; (2) electrochemical oxidation of these metal particles to MOn/2, and; (3) displacement of the oxygen from MOn/2 using HX (for example) to yield nanoparticles of MX. This conversion from metal to metal oxide to metal salt occurs on a particle-by-particle basis; that is, each metal nanoparticle is converted into a semiconductor nanoparticle. E/C-synthesized -CuI and CdS quantum dots possess many of the attributes of quantum dots synthesized using molecular beam epitaxy, including epitaxial orientation on the graphite surface, a narrow size dispersion, and strong, particle size-tunable photoluminescence. However, the E/C method is faster, cheaper, and applicable to a greater number of materials.

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Section: Electrodeposition Of Size-monodisperse Metal Nanoparticlesmentioning

confidence: 78%

Hybrid Electrochemical/Chemical Synthesis of Quantum Dots

Penner

2000

Acc. Chem. Res.

115

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“…[20][21][22][23] Electrodeposition has also been used for synthesis of metal nanocrystallites on carbon based substrates such as highly oriented pyrolytic graphite (HOPG). [24][25][26] Finot et al have reported synthesis of gold nanocrystals by applying a potential step to GC as the substrate for a specific time (5 s) using dilute solutions of KAuCl 4 (1.0 × 10 -5 -2.0 × 10 -4 M) in H 2 SO 4 (0.5 M) and applying different overpotentials to investigate the effect of concentrations and potential on particle size. 27,28 The effects of substrates, additives (iodide ions and cysteine) and deposition times on the size, morphology and crystallographic orientation of gold have been studied by El-Deab et al by using GC, HOPG and gold electrodes in acidic medium containing gold salt.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Deposition of Gold Nanoparticles on Pencil Graphite by Fast Scan Cyclic Voltammetry

Etesami

Karoonian

Mohamed

2011

J Chinese Chemical Soc

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Gold nanoparticles (AuNPs) were electrodeposited on the surface of pencil graphite (PG) by fast scan cyclic voltammetry without using any additives in acidic medium. The effect of deposition time on the size of electrodeposited AuNPs was investigated in sulfuric acid as a supporting electrolyte. The deposition time was varied by varying the scan rate, number of cycles and applied potential range. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used for characterization of PG and electrodeposited AuNPs. The results confirmed that nanosized gold particles (20 ± 8 nm) were deposited on the PG substrate with almost spherical geometry.

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“…13,24 The driving force for this process has been suggested to be related to the presence of incompletely oxidized functionalities existing at terraces and kink sites on freshly cleaved HOPG surface. 13 Here, we immersed an as-cleaved HOPG into 0.5 M H 2 SO 4 containing electrochemically dissolved Pt ions to evaluate the chemical interaction between dissolved Pt ions and HOPG. As seen in Figure 2, individual Pt nanoparticles can be observed at the edge sites on the HOPG surface, which indicates that dissolved Pt ions have properties similar to PtCl 6 2− .…”

Section: Resultsmentioning

confidence: 99%

“…The individual Pt nanoparticles have an average diameter of 10-20 nm with height of about 1.5-2.5 nm, similar in geometry to Pt nanoparticles reduced on the edge sites of HOPG from PtCl 6 2− . 13,24 It is assumed that the dissolved Pt ions are spontaneously reduced by the incompletely oxidized functionalities at the edge sites, analogous to the case for PtCl 6 2− . 13 The characteristic plate-like morphology may come from the high mobility of as-reduced Pt on the HOPG surface leading to a two-dimensional growth.…”

Section: Resultsmentioning

confidence: 99%

Model Electrode Studies of the Electrostatic Interaction between Electrochemically Dissolved Pt Ions and RuO₂Nanosheets

Sannegowda

Chauvin

et al. 2013

J. Electrochem. Soc.

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Model electrodes consisting of ruthenium oxide nanosheets coated on freshly cleaved highly oriented pyrolytic graphite (RuO 2 nanosheet/HOPG) were prepared to investigate the electrostatic interactions between RuO 2 nanosheets and electrochemically dissolved Pt ions. The RuO 2 nanosheet/HOPG model electrode was dipped into a solution containing dissolved Pt ions generated by potential cycling a Pt working electrode in sulfuric acid electrolyte. Scanning tunneling microscopy revealed preferential adsorption of Pt ions on the nanosheets as island-like deposits, while no such deposits were observed on HOPG. This shows the strong electrostatic interactions between the positively-charged Pt ions and negatively-charged nanosheet. The calculated amount of Pt ions adsorbed was 0.93 × 10 6 atoms μm −2 , which agreed with the theoretical saturated adsorption amount of Pt ion on RuO 2 nanosheet of 0.96 × 10 6 atoms μm −2 . All of the Pt ions could be electrochemically reduced to Pt nanoparticles showing activity toward the oxygen reduction reaction. Platinum supported on carbon (Pt/C) is widely used as a cathode catalyst in polymer electrolyte fuel cells because of its high oxygen reduction reaction (ORR) activity. The loss of electrocatalytic activity during fuel cell operation is a detrimental factor to the useful lifetime of commercial polymer electrolyte fuel cell systems. Hence, there is a strong demand to improve the durability of electrocatalyst to realize the wide-spread commercialization of polymer electrolyte fuel cells. Numerous studies have clarified that dissolution, migration and/or sintering of platinum nanoparticles on carbon are vital degradation factors of the cathode catalyst. [1][2][3] Oxides that are stable under acidic and oxidizing conditions have been suggested to enhance the durability of Pt as cathode catalysts. For example, SnO 2 has been proposed as an alternative support to replace carbon to enhance the durability of Pt catalyst due to its resistance to corrosion. 4 TiO 2 added to Pt/C was suggested to anchor platinum particles, preventing agglomeration and coalescence during durability testing. 5,6 Carbon supported Pt covered with a thin layer of SiO 2 has been shown to exhibit high stability during potential cycling in H 2 SO 4 electrolyte. 7,8 The foundation of the increase in durability due to the addition of these oxides is not well understood. In addition, due to the poor conductivity of these oxides, the original properties of Pt/C are often inevitably obstructed, which includes the loss of initial electrochemical surface area (ECSA) and ORR activity with the addition of oxides.Contrary to most other oxide systems, RuO 2 nanostructures possess excellent electronic conductivity and electrochemical stability, making them an ideal additive that would not obstruct electrode kinetics. Indeed, we and others have found that the combination of RuO 2 nanostructures and Pt nanoparticles can enhance ORR properties. For example, incorporation of carbon-supported RuO 2 (RuO 2 /C) to Pt was found to a...

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Electrochemical Preparation of Platinum Nanocrystallites with Size Selectivity on Basal Plane Oriented Graphite Surfaces

Cited by 309 publications

References 37 publications

Hybrid Electrochemical/Chemical Synthesis of Quantum Dots

Hybrid Electrochemical/Chemical Synthesis of Quantum Dots

Electrochemical Deposition of Gold Nanoparticles on Pencil Graphite by Fast Scan Cyclic Voltammetry

Model Electrode Studies of the Electrostatic Interaction between Electrochemically Dissolved Pt Ions and RuO₂Nanosheets

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Electrochemical Preparation of Platinum Nanocrystallites with Size Selectivity on Basal Plane Oriented Graphite Surfaces

Cited by 309 publications

References 37 publications

Hybrid Electrochemical/Chemical Synthesis of Quantum Dots

Hybrid Electrochemical/Chemical Synthesis of Quantum Dots

Electrochemical Deposition of Gold Nanoparticles on Pencil Graphite by Fast Scan Cyclic Voltammetry

Model Electrode Studies of the Electrostatic Interaction between Electrochemically Dissolved Pt Ions and RuO2Nanosheets

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Model Electrode Studies of the Electrostatic Interaction between Electrochemically Dissolved Pt Ions and RuO₂Nanosheets