Synthesis and characterization of small platinum particles formed by the chemical reduction of chloroplatinic acid

Rheenen, P.R. Van; McKelvy, M.J.; Glaunsinger, W. S.

doi:10.1016/0022-4596(87)90350-1

Cited by 95 publications

(48 citation statements)

References 25 publications

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“…To the best of our knowledge, this is the smallest Pt:PVP crystallite synthesized in aqueous phase reduction of Pt ions reported so far [19][20][21]. The broadened and low diffraction peak at Pt (111) as well as little shift to the smaller angle (from 40°) suggests the formation of a large number of vacancies associated with higher population of low-coordination sites in smaller Pt clusters [32].…”

Section: Structural Characterizationmentioning

confidence: 76%

“…ions to Pt 0 by NaBH 4 is the most suitable method for synthesizing small and monodisperse Pt clusters but the produced Pt 0 readily reacts with borohydride (BH 4 -) causing incomplete reduction of the precursor ions, which results a very low yield along with larger particles formation [19][20][21][22]. Hence, fresh BH 4 -should be supplied continuously to reduce metal ions and separate the produced Pt 0 from the reaction mixture.…”

Section: Size Distributionsmentioning

confidence: 99%

“…Commonly used procedures include Pt 4? or Pt 2? salts reduction by borohydride [12][13][14][15][16], hydrogen [17,18], alcohol [19][20][21][22][23][24], glycol [25,26], or ethylene glycol [27,28] in the presence of a stabilizer or on a solid support. Despite a large choice of synthetic protocols, an accurate control of the particle size, simple and reproducible synthetic strategies are important to investigate their physical and chemical properties.…”

Section: Introductionmentioning

confidence: 99%

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Optimized reduction conditions for the microfluidic synthesis of 1.3 ± 0.3 nm Pt clusters

et al. 2015

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Recently, small (\2 nm) and monodispersed Pt clusters has gained much attention due to their high catalytic activity in the aerobic oxidations. However, the chemical synthesis of small Pt clusters is not trivial; high temperature is often required to completely reduce the Pt 4?/2? ions to Pt 0 , which accelerates the growth of the Pt clusters. Here, we discussed a very simple microfluidic reduction of Pt 4? to Pt 0 by NaBH 4 in the presence of PVP that produces \2 nm Pt clusters in any variable reduction conditions. The microfluidic reduction conditions were optimized for the synthesis of possible smallest Pt clusters in terms of five reaction parameters: (1) temperature, (2) concentration of H 2 PtCl 6 , (3) molar ratio of NaBH 4 to Pt 4? ions, (4) molar ratio of PVP-monomer to Pt 4? ions, and (5) molecular weight/chain length of PVP. We found that possible smallest particles with average diameter 1.3 ± 0.3 nm were produced when aqueous solutions of H 2 PtCl 6 (4 mM) and NaBH 4 (40 mM) containing PVP (160 mM) were injected into the micromixer placed in an icebath at a flow rate of 200 mL/h. The produced particles were characterized by UV-visible absorption spectrophotometry, powder X-ray diffractometry and transmission electron microscopy.

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Section: Structural Characterizationmentioning

confidence: 76%

Section: Size Distributionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optimized reduction conditions for the microfluidic synthesis of 1.3 ± 0.3 nm Pt clusters

et al. 2015

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“…Utilization of simple laboratory equipments and easy procedure to obtain small and uniform metal NPs made chemical reduction method unparallel for NPs synthesis. Pt-NPs are prepared in general, via the chemical reduction of Pt ions by borohydride (Van Rheenen et al, 1987;Knecht et al, 2008), hydrogen (Ahmadi et al 1996), alcohols (Toshima et al, 1991;Teranishi et al, 1999), glycol or ethylene glycol (Herricks et al, 2004) in the presence of a stabilizer or on a solid support. Despite a large choice of synthetic protocols, an accurate control of the particle size, simple and economical strategies for synthetic method is most important to investigate their novel physical and chemical properties.…”

Section: Introductionmentioning

confidence: 99%

Tunable synthesis of platinum nanoparticles by EtOH reduction in presence of poly (vinylpyrrolidone)

Rahman

Akhter²,

Ahmed

et al. 2015

Bangladesh J. Sci. Ind. Res.

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Monodispersed platinum nanoparticles (Pt-NPs) with an average diameter dTEM 3.1±1.0 nm were synthesized by EtOH reduction method in the presence of an organic polymer poly (vinylpyrrolidone) (PVP) with an average molecular weight of 40,000. Using this particles as seed, size tunable Pt-NPs of d TEM 3.1±1.0 nm to 5.7±1.6 nm with sufficient monodispersity were synthesized by multiple step seeding growth. Formation of Pt-NPs was confirmed by the UV-visible absorption spectra. Transmission electron micrographs (TEM) and powder X-ray diffraction (XRD) patterns confirmed that the particles were single crystalline with fcc crystal geometry.Key words: Platinum; EtOH; Nanoparticles; PVP; Synthesis Available online at www.banglajol.info Bangladesh J. Sci. Ind. Res. 50(2), [87][88][89][90][91][92] 2015 *Corresponding author: E-mail: smjakir080@yahoo.com Chemical syntheses offer a versatile route allowing tailoring of the properties of materials by assembling atoms and particles from the atomic or molecular state to the macroscopic scale (Elechiguerra et al., 2006). The characteristics of the crystals can be controlled by the thermodynamics and kinetics of the synthesis (Goia, 1998) and the great progress has been made. However, there is still need for development of chemical methods that can tailor the morphology of Pt crystals at different scales.This article describes a simple preparation and size control of small Pt-NPs stabilized by PVP with narrow size distribution by EtOH reduction method. The nanoparticles were characterized by UV-Visible optical spectroscopy, transmission electron microscopy (TEM) and powder x-ray diffractometry (XRD). Materials and methods Chemicals and materialsHydrogen hexachloroplatinate(IV) hexahydrate (H 2 PtCl 6 .6H 2 O) (Sigma-Aldrich), ethanol (C 2 H 6 O) (Merck), Poly(vinylpyrrolidone) (PVP, MW 40,000) (TCI), were of analytical grade and used as received. Double distilled water was used to prepare aqueous solutions. All of the glasswares along with teflon coated magnetic stirrer were cleaned with aqua regia for fine cleaning followed by rinsing with double distilled water. Preparation of Pt:PVP NPsAs reported earlier (Hossain et al., 2012, Teranishi et al., 1999, a mixture of ethanol/water solution (9:1, v/v, 100 mL; 90% EtOH) containing H 2 PtCl 6 (30 mM, 3.34 mL) and PVP (444 mg, PVP-monomer/Pt = 40:1) was refluxed at 90 °C in a 150 mL round bottom flask for 3 h using water bath. After cooling to room temperature, the produced Pt:PVP was purified using a dialysis membrane of cut off molecular weight 10 kDa for the removal of inorganic ions and ethanol. Finally, the purified sample was stored in an air tight desiccators after freeze drying. Larger Pt:PVP by seed mediated growthTo form larger Pt-NPs, smaller Pt:PVP NPs were used as seed particles. In a typical procedure, a mixture of total 25 mL aqueous solution of H 2 PtCl 6 (10 mM, 2.5 mL) and ethanol/water solution (9:1, v/v, 22.5 mL) were added to the 25 mL of Pt:PVP seed solution of 1.0 mM concentration. The final concentr...

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“…The processes of synthesis of Au, Pt and Ag nano-particles by chemical reduction with citrate are common. [25][26][27][28] The first stage of these processes is believed to be the decarboxylation of citrate on Au catalytic surface and formation of acetone-1, 3-dicarboxylate according to the following Scheme 1: 2 and NiO, which are present on the surface of the deposits, can also be involved in catalytic decomposition of citrate as well as in the catalysis pathway of Re and Ni electrodeposition in processes (2) and (3) above. This statement is justified by the fact that oxides of Ni and Re are known catalysts for different chemical and electrochemical reactions.…”

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confidence: 99%

Characterization of Re-Ni Films after the Initial Stages of Electrodeposition

Berkh

Burstein

Gladkikh

et al. 2016

J. Electrochem. Soc.

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Re-Ni layers produced in the early stages of electrodeposition from citrate electrolytes were studied by high-resolution X-ray photoelectron spectroscopy (HR-XPS) and time-of-flight secondary-ion mass spectrometry (TOF-SIMS). The deposition time was varied in the range of 2 to 300 seconds. The compositional heterogeneity of the thin Re-Ni alloys and the variations of their composition with deposition time, both in the bulk and on the surface, were shown. The results obtained are indicative of the occurrence of chemical reactions at short deposition times and are in agreement with our previous results obtained in studying the early stages of Re-Ni deposition by electrochemical techniques. The mechanism of the deposition process is discussed. Induced electrodeposition of refractory metals with iron-group metals has drawn the attention of many researchers in view of their high corrosion resistance, stability at high temperatures and wear resistance.1 Induced codeposition of rhenium from aqueous solutions has been studied, 2-5 including Re-Ni alloys from citrate-containing solutions. [6][7][8][9] Induced codeposition of Re from an electrolyte containing ReO − 4 can occur readily. Coatings with a thickness of up to 25 μm were obtained within 60 min deposition at a faradaic efficiency of up to 95%. Moreover, the concentration of Re in the resulting alloy can reach up to 90 at.%. This excludes the possibility of having a precursor similar to that found in the case of W, 1,10-12 since it would require the formation of a complex containing nine molecules of the perrhenate ion, which is totally unlikely. Instead, we have suggested a new mechanism, according to which the Ni 2+ ion is first reduced and deposited on the surface of the substrate. The resulting neutral Ni atoms act as strong reducing agents, helping to reduce the 7-valent ReO − 4 probably to the 5-valent ReO − 3 . This is a typical catalytic process, in which the Ni 2+ ion acts as a catalyst, the concentration of which should not change in the overall reaction. Theoretically, this should lead to a deposit of pure Re, but some Ni is found in the resulting alloy due to entrapment of neutral Ni atoms. This represents a rather unique type of process, where the catalyst is formed in situ as part of the redox process.6-9 The deposition of Re-Ni apparently depends on the high catalytic activity of the freshly deposited nickel. We have supported this hypothesized mechanism by different experiments. 7,[13][14][15] The initial stages of Re-Ni deposition, which are critical for understanding the catalytic mechanism, were studied in our recent work. 13There, the electrodeposition of Re-Ni alloys was investigated at deposition times of 0.05-60 s, unlike in earlier publications, 6-8 where the deposition times were on the scale of minutes and hours. The anomalous faradaic efficiency (AFE) of the deposition process, the composition of the deposits and their morphology were considered. The AFE and the Re-content in the deposits were shown to decrease with deposition time. Anom...

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Synthesis and characterization of small platinum particles formed by the chemical reduction of chloroplatinic acid

Cited by 95 publications

References 25 publications

Optimized reduction conditions for the microfluidic synthesis of 1.3 ± 0.3 nm Pt clusters

Optimized reduction conditions for the microfluidic synthesis of 1.3 ± 0.3 nm Pt clusters

Tunable synthesis of platinum nanoparticles by EtOH reduction in presence of poly (vinylpyrrolidone)

Characterization of Re-Ni Films after the Initial Stages of Electrodeposition

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