Formation Of Platinum Nanoparticles Research Articles

Prunella vulgaris-phytosynthesized platinum nanoparticles: Insights into nanozymatic activity for H2O2 and glutamate detection and antioxidant capacity

Artificial nanozymes (enzyme-mimics), specifically metallic nanomaterials, have garnered significant attention recently due to their reduced preparation cost and enhanced stability in a wide range of environments. The present investigation highlights, for the first time, a straightforward green synthesis of biogenic platinum nanoparticles (PtNPs) from a natural resource, namely Prunella vulgaris (Pr). To demonstrate the effectiveness of the phytochemical extract as an effective reducing agent, the PtNPs were characterized by various techniques such as UV–vis spectroscopy, High-resolution Transmission electron microscopy (HR-TEM), zeta-potential analysis, Fourier-transform infrared spectroscopy (FTIR), and Energy dispersive spectroscopy (EDS). The formation of PtNPs with narrow size distribution was verified. Surface decoration of PtNPs was demonstrated with multitudinous functional groups springing from the herbal extract. To demonstrate their use as viable nanozymes, the peroxidase-like activity of Pr/PtNPs was evaluated through a colorimetric assay. Highly sensitive visual detection of H2O2 with discrete linear ranges and a low detection limit of 3.43 μM was demonstrated. Additionally, peroxidase-like catalytic activity was leveraged to develop a colorimetric platform to quantify glutamate biomarker levels with a high degree of selectivity, the limit of detection (LOD) being 7.00 μM. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) test was used to explore the scavenging nature of the PtNPs via the degradation of DPPH. Overall, the colorimetric assay developed using the Pr/PtNP nanozymes in this work could be used in a broad spectrum of applications, ranging from biomedicine and food science to environmental monitoring.

Kinetic and thermodynamic study of ALP enzyme in the presence and absence MWCNTs and Pt-NPs nanocomposites

In this study, nanocomposite materials including multi-wall carbon nanotubes (MWCNTs) coated with platinum nanoparticles (Pt-NPs) were synthesized. The formation of Pt-NPs using green chemistry method and MWCNTs from waste synthetic oil was characterized using TEM, FESEM, AFM, and FTIR techniques. The diameter of prepared Pt-NPs and MWCNTs was in the different ranges of nanometer26.80–44.66 nm and 56.49–89.38 nm respectively. Raman and EDX techniques were employed to confirm MWCNT-COOPt and MWCNT-Pt formation. ALP dephosphorylates various natural substrates, and high levels of alkaline phosphatase are linked to a variety of diseases, including dynamic bone disease, hepatitis, and prostate cancer. This study aims to determine the kinetic and thermodynamic parameters of ALP enzyme in the presence/ or absence of nano materials unlike Pt-NPs. The Vmax value of ALP without NPs was 0.931 × 10-3 mol mL−1 min−1, while in the presence of nanomaterials, the Vmax had values of 1.207 × 10-3, 1.145 × 10-3, 1.249 × 10-3, and 0.975 × 10-3 mol mL−1 min−1, the Km value was decreased with increasing of NPs concentration in the Pt NPs. Km values were 0.118, 0.106, 0.191, and 0.098, and the Vmax/Km ratio were 10.20, 10.74, 6.51, and 9.86 min−1 at 80 mg/mL of MWCNT-Pt, MWCNT-COOPt, MWCNT-COO, and Pt-NPs respectively. The results revealed that the kinetic parameters (Vmax, Km, and Vmax/Km) and thermodynamic parameters (ΔH*, ΔE, ΔS* and ΔG*) were slightly increased as the concentration of MWCNT-based nanomaterials increased. This effect might be due to changes in enzyme configuration following immobilization.

Controlled Synthesis of Platinum and Silver Nanoparticles Using Multivalent Ligands

Here, the controlled formation of platinum nanoparticles (PtNPs) and silver nanoparticles (AgNPs) using amine-functionalized multivalent ligands are reported. The effects of reaction temperature and ligand multivalency on the growth kinetics, size, and shape of PtNPs and AgNPs were systematically studied by performing a stepwise and a one-step process. PtNPs and AgNPs were prepared in the presence of amine ligands using platinum (II) acetylacetonate and silver (I) acetylacetonate, respectively. The effects of ligands and temperature on the formation of PtNPs were studied using a transmission electron microscope (TEM). For the characterization of AgNPs, additionally, ultraviolet-visible (UV-Vis) absorption was employed. The TEM measurements revealed that PtNPs prepared at different temperatures (160–200 °C, in a stepwise process) are monodispersed and of spherical shape regardless of the ligand multivalency or reaction temperature. In the preparation of PtNPs by the one-step process, ligands affect the shape of the PtNPs, which can be explained by the affinity of the ligands. The TEM and UV-Vis absorption studies on the formation of AgNPs with mono-, di-, and trivalent ligands showed narrower size distributions, while increasing the temperature from 80 °C to 120 °C and with a trivalent ligand in a one-step process.

In Situ Small-Angle X-ray Scattering Studies on the Growth Mechanism of Anisotropic Platinum Nanoparticles

Shape-controlled platinum nanoparticles exhibit extremely high oxygen reduction activity. Platinum nanoparticles were synthesized by the reduction of a platinum complex in the presence of a soft template formed by organic surfactants in oleylamine. The formation of platinum nanoparticles was investigated using in situ small-angle X-ray scattering experiments. Time-resolved measurements revealed that different particle shapes appeared during the reaction. After the nuclei were generated, they grew into anisotropic rod-shaped nanoparticles. The shape, size, number density, reaction yield, and specific surface area of the nanoparticles were successfully determined using small-angle X-ray scattering profiles. Anisotropic platinum nanoparticles appeared at a low reaction temperature (∼100 °C) after a short reaction time (∼30 min). The aspect ratio of these platinum nanoparticles was correlated with the local packing motifs of the surfactant molecules and their stability. Our findings suggest that the interfacial structure between the surfactant and platinum nuclei can be important as a controlling factor for tailoring the aspect ratio of platinum nanoparticles and further optimizing the fuel cell performance.

Biofabricated platinum nanoparticles: therapeutic evaluation as a potential nanodrug against breast cancer cells and drug-resistant bacteria.

Use of plant extracts for the synthesis of various metal nanoparticles has gained much importance recently because it is a simple, less hazardous, conservative and cost-effective method. In this research work, platinum nanoparticles were synthesized by treating platinum ions with the leaf extract of Psidium guajava and their structural properties were studied using various characterization techniques. The formation of platinum nanoparticles was confirmed by the disappearance of the absorbance peak at 261 nm in UV-visible spectra. The results of gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FT-IR) analysis showed functional moieties responsible for bio-reduction of metal ions and stabilization of platinum nanoparticles. The use of dynamic light scattering (DLS) imaging techniques confirmed the formation of stable monodispersed platinum nanoparticles showing a zeta potential of −23.4 mV. The morphological examination using high resolution transmission electron microscopy (HR-TEM) and Scanning electron microscopy (SEM) confirmed the formation of spherical platinum nanoparticles with an average diameter of 113.2 nm. X-ray powder diffraction (XRD) techniques showed the crystalline nature of biosynthesized platinum nanoparticles with a face-centered cubic structure. The results of energy-dispersive X-ray spectroscopy (EDAX) showed 100% platinum content by weight confirming the purity of the sample. The cytotoxic effect of biosynthesized platinum nanoparticles assessed in a breast cancer (MCF-7) cell-line by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, revealed an IC50 of 167.2 μg ml−1. The results of a wound healing assay showed that treatment with platinum nanoparticles induced an anti-migratory effect on MCF-7 cells. In the cell cycle phase distribution, treatment with platinum nanoparticles inhibited cell proliferation as determined by flow cytometry with PI staining. Significant cell cycle arrest was detected at the G0/G1 phase with a notable decrease in the distribution of cells in the S and G2/M phases. The anti-bacterial activity of bio-synthesized platinum nanoparticles was evaluated against four pathogenic bacteria i.e. B. cereus (Gram positive), P. aeruginosa (Gram negative), K. pneumonia (Gram negative) and E. coli (Gram negative). The biosynthesized platinum nanoparticles were found to show dose-dependent inhibition against pathogenic bacteria with a significant effect on Gram-negative bacteria compared to Gram-positive bacteria. This synergistic blend of green and simplistic synthesis coupled with anti-proliferative and anti-bacterial properties makes these biogenic nanoparticles suitable in nanomedicine.

Pt–ZnO/M (M = Fe, Co, Ni or Cu): A New Promising Hybrid-Doped Noble Metal/Semiconductor Photocatalysts

In the present paper, a simple and fast one pot process to prepare hybrid metal/semiconductor nanocomposites (NCs) using a simple polyol method is discussed. The Nanoparticle sizes of the hybrid nanocomposite range between 20 and 30 nm. This protocol involves the use only of 1,3 propanediol as solvent and platinum(IV) and zinc(II) as precursors without the need to use any surfactant or reducing agent. The formation of platinum nanoparticles (PtNPs) was observed first (before the boiling point) followed by the zinc oxide (ZnO) nanoparticles which started to form when the temperature reached boiling point (190 °C). The reaction then continued for 30 min. To study the doping effect on the optical properties of the hybrid nanomaterials obtained, Cu(II), Fe(II), Co(II) and Ni(II) were used as cationic dopants. The same protocol was maintained with the only exception being that the required amount of the doping element was added according to a well determined ratio (R = Zn(II):M(II), where M = Cu, Fe, Co, or Ni). Full characterization was conducted using various techniques (such as X-ray diffraction, transmission electron microscopy, DTA/TGA, X-ray fluorescence, etc.) to reveal the purity, morphology, stability and the intrinsic properties of the obtained hybrid Pt–ZnO/M nanocomposites (where M = Cu, Fe, Co or Ni). Compared to bare ZnO or Pt–ZnO, the new hybrid NCs exhibit a better stability (up to 600 °C) and an important change in the optical properties. This change makes them new promising hybrid nanomaterials for many applications especially in photocatlytic and renewable energy applications.

Electrocatalytic Activities of Gold Nanoparticles on Glassy Carbon Prepared By Simple Electrochemical Method

Nanoparticles (NPs) of noble metals such as gold and platinum are utilized in a wide range of applications in various fields because of their unique catalytic, electronic, and optical properties. Furthermore, NPs have large surface area to volume ratio, which leads to an increase in catalytic efficiency and also to a cost-reduction. A variety of methods using chemical reactions are currently available for synthesizing NPs in solution phase and also for controlling their shapes and properties. In the field of electrochemistry, platinum NPs (PtNPs) deposited on carbon materials such as graphite, glassy carbon, and carbon blacks have been extensively studied because they are useful as efficient electrocatalysts for fuel cells, water electrolysis, and so on. Nishimura et al. have developed a simple method for preparing shape-controlled PtNPs on a graphite surface [1]. In the method, the water electrolysis (2H2O → 2H2 + O2) was conducted at a constant current using the graphite electrode and a Pt electrode as the cathode and anode, respectively. The galvanostatic electrolysis was carried out for several hours in a strong acid solution such as HNO3 and H2SO4. During the electrolysis, the Pt anode slightly dissolved to form a small amount of Pt ions whereas the graphite cathode reduced the ions resulting in the formation of PtNPs. The method was cost friendly because PtNPs were obtained without any reducing and stabilizing agents, and also because 72 % of dissolved Pt ions were electrodeposited as PtNPs. In our previous report [2], we have shown that gold NPs (AuNPs) can be produced by galvanostatic electrolysis using an Au anode and a graphite cathode. This electrolysis was essentially the same as the simple method that has been used to prepare PtNPs [1]. The Au anode, where oxygen evolution occurred, dissolved to form Au ions (Au → Au3+ + 3e-) and the graphite cathode, where hydrogen evolution occurred, reduced them (Au3+ + 3e- → Au). We recently employed the galvanostatic electrolysis in order to prepare AuNPs on glassy carbon (GC). The experimental setup is shown in Figure 1a. AuNPs were uniformly deposited by conducting the electrolysis for two hours in 0.5 M H2SO4 solution, as can be seen in the SEM image (Figure 1b). Interestingly, the AuNPs showed a good electrocatalytic activity toward the reduction of nitrobenzene (C6H5NO2 + 6H+ + 6 e- → C6H5NH2 + 2H2O) compared with Au-wire electrode (Figures 1c and 1d). This is probably because AuNPs are enclosed by (111) planes, which will be discussed in the presentation. REFERENCES [1] T. Nishimura, T. Nakade, T. Morikawa, H. Inoue, Electrochimi. Acta, 129 (2014) 152. [2] Y. Mukouyama, Y. Fukuda, T. Nishimura, ECS Trans., 80 (2017) 1425. [3] Z. Chen, Z. Wang, D. Wu, L. Ma, J. Hazard Mater, 197 (2011) 424. FIGURE CAPTION Figure 1. (a) A schematic of the experimental setup for the simple galvanostatic electrolysis. Electrolysis solution: 0.5 M H2SO4. Cathode: GC disc. Anode: Au wire. (b) A SEM image of the GC cathode taken after conducting the electrolysis at 30℃ for two hours. Cathodic and anodic current densities were 10 and 2.5 mA cm-2, respectively. (c and d) Cyclic votammograms (CVs) measured in 0.1 M H2SO4 + 0.016 M nitrobenzene (NB) at a potential scan rate of 0.1 Vs-1. The working electrode used was (c) the AuNPs/GC electrode (total surface area of AuNPs: 0.16 cm2) and (d) an Au-wire electrode (surface area: 2.58 cm2). When the electrode potential (E) < ca. 0.2 V, NB was reduced to form aniline via a two-step reaction (see ref [3]): the formation of phenylhydroxylamine (C6H5NO2 + 4H+ + 4e- → C6H5NHOH + H2O) and its consecutive reduction to aniline (C6H5NHOH + 2H+ + 2e- → C6H5NH2 + H2O). Figure 1

Laser-induced formation of Au/Pt nanorods with peroxidase mimicking and SERS enhancement properties for application to the colorimetric determination of H2O2.

Platinum nanoparticles (PtNPs)were uniformly grown on the surface of gold nanorods (AuNRs) by a laser irradiation procedure. Transmission electron microscopy confirmed that the PtNPs are uniformly grown on the surface of theAuNRs. The formation of PtNPs on the AuNRs leads to a red-shift of the absorption maximum from 734nm to 766nm. In addition, the efficiency of surface enhanced Raman scattering (SERS) is increased, but the photothermal conversion efficiency is decreased compared to pure AuNRs. The result indicates that electron transfer occurs between gold and platinum. The peroxidase mimicking effect of PtNPs, AuNRs and Au/Pt NRs by catalyzing the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxidized 3,3',5,5'-tetramethylbenzidine (oxTMB; a quinone) in the presence of H2O2. The catalytic activity of Au/Pt NRs is higher than that of sole AuNRs or PtNPs by factors of4.2 and 2.1, respectively. Thus, Au/Pt NRs have been used for the detection of peroxide and the limit of detection is 0.04μM. This work provides an approach to integrate the peroxidase mimicking effect with SERS enhancement for potential application in detection. Graphical abstract A schematic diagram for the laser-induced growth of Au/Pt NRs and the colorimetric determination of hydrogen peroxide concentration with their peroxidase mimicking properties. The limit of detection is 0.04μM based on the use ofAu/Pt NRs as acatalyst.

From Single Atoms to Nanoparticles: Autocatalysis and Metal Aggregation in Atomic Layer Deposition of Pt on TiO2 Nanopowder.

A fundamental understanding of the interplay between ligand-removal kinetics and metal aggregation during the formation of platinum nanoparticles (NPs) in atomic layer deposition of Pt on TiO2 nanopowder using trimethyl(methylcyclo-pentadienyl)platinum(IV) as the precursor and O2 as the coreactant is presented. The growth follows a pathway from single atoms to NPs as a function of the oxygen exposure (PO2 × time). The growth kinetics is modeled by accounting for the autocatalytic combustion of the precursor ligands via a variant of the Finke-Watzky two-step model. Even at relatively high oxygen exposures (<120 mbar s) little to no Pt is deposited after the first cycle and most of the Pt is atomically dispersed. Increasing the oxygen exposure above 120 mbar s results in a rapid increase in the Pt loading, which saturates at exposures >> 120 mbar s. The deposition of more Pt leads to the formation of NPs that can be as large as 6 nm. Crucially, high PO2 (≥5 mbar) hinders metal aggregation, thus leading to narrow particle size distributions. The results show that ALD of Pt NPs is reproducible across small and large surface areas if the precursor ligands are removed at high PO2 .

The Formation of Metal-Catalyst Nanoparticles by the Hydrosol Method in TWEEN-20 Aqueous Solution and Conditions for Their Uniform Distribution on a Carbon Carrier Surface

Conditions for the formation of metal-catalyst nanoparticles in an aqueous medium by the hydrosol method in the presence of surfactant are studied. Based on the study of the colloidal chemical properties of the preparation TWEEN-20, which is a polyoxyethylene sorbitan monolaurate containing, in addition to TWEEN-20 itself, impurities of other fatty alkyl esters and fatty acids, the possibility of its use in the synthesis of an electrocatalyst, including platinum, as a dispersion stabilizer of freshly formed particles is shown. The formation of platinum nanoparticles and their uniform distribution over the surface of the carbon carrier is confirmed by transmission electron microscopy, small-angle X-ray scattering, and X-ray-diffraction analysis.

Biofabrication of platinum nanoparticles using Fumariae herba extract and their catalytic properties.

Due to the increasing popularity of using plant extract in the synthesis of nanoparticles, this study presented the synthesis of platinum nanoparticles using Fumariae herba extract. The formation of platinum nanoparticles was confirmed by UV–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) with EDS profile. Transmission electron micrograph presented the hexagonal and pentagonal shape of the synthesized nanoparticles sized about 30 nm. Moreover, platinum nanoparticles presented good catalytic properties in the reduction of methylene blue and crystal violet.

Synthesis of platinum nanoparticles by nanosecond laser irradiation of bulk Pt in different polar solvents

Formation of platinum nanoparticles (Pt NPs) by Nd:YAG laser ablation of a platinum target in polar solvents, viz. distilled water (DW), absolute ethanol (ET), acetone (AC), and ethylene glycol (EG), was investigated. Characterization of the NPs in terms of size distribution, shape, optical properties, phase structure, crystalline nature, and molecular structure was carried out as a function of the nature of the liquid by transmission electron microscopy, scanning electron microscopy, ultraviolet–visible (UV–Vis) absorption spectroscopy, X-ray diffraction analysis, selected-area electron diffraction analysis, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The interaction of the ablation plasma plume species with species produced by decomposition of the liquid resulted in formation of spherical Pt and PtO NPs with diameter ranging from 5 nm up to a maximum of 104 nm. The results evidence that the properties of the NPs were affected by the nature of the liquid, including thermodynamic parameters such as the dipole moment, boiling point, and viscosity.

Electrochemical formation and properties of polymethylolacrylamide film with inclusion of platinum particles

The possibility of single-stage formation of a polymethylolacrylamide/Pt composite by the electropolymerization technique is studied. The optimum process parameters are determined. It is found that addition of chloroplatinic acid (H2PtCl6 · 6H2O) to the monomer composition results in partial inhibition of electropolymerization and a drastic decrease in the rate of polymer film formation on a stainless steel cathode in the mode of potentiostatic electrolysis. It is found that addition of chitosan to electrolyte intensifies inclusion of Pt into the polymer matrix through formation of its complex with H2PtCl6 · 6H2O, as confirmed by NMR studies. The time of formation of the complex does not exceed 30–60 min. Reduction of the complex results in simultaneous formation of platinum nanoparticles in the polymer matrix and in their stabilization by the insoluble chitosan phase. The content of platinum in the composite grows at an increase in the concentration of H2PtCl6 · 6H2O and reaches 25.15 at %. The regularities of polymer deposit distribution over the metal surface, morphology, particle size, and elemental composition of composites was studied using impedance spectroscopy, X-ray phase analysis, and scanning field–emission electron microscopy. The method of cyclic voltammetry was used to establish the electrochemical properties of metal/polymer composite films. It is shown that polymer methylolacrylamide films modified by chitosan and platinum manifest electrocatalytic activity with respect of oxidation of ethanol.

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

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 dTEM 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.Bangladesh J. Sci. Ind. Res. 50(2), 87-92, 2015

Correction: The in situ formation of platinum nanoparticles and their catalytic role in electroactive phase formation in poly(vinylidene fluoride): a simple preparation of multifunctional poly(vinylidene fluoride) films doped with platinum nanoparticles

Correction: The in situ formation of platinum nanoparticles and their catalytic role in electroactive phase formation in poly(vinylidene fluoride): a simple preparation of multifunctional poly(vinylidene fluoride) films doped with platinum nanoparticles

Platinum nanoparticles incorporated in silsesquioxane for use in LbL films for the simultaneous detection of dopamine and ascorbic acid

We describe the preparation of platinum nanoparticles (PtNPs) using the 3-n-propylpyridinium silsesquioxane chloride (SiPy+Cl−) as a nanoreactor and stabilizer. The formation of PtNPs was monitored by UV–Vis spectroscopy by measuring the decrease in the intensity of the band at 375 nm, which is attributed to the electronic absorption of PtCl6 2− ions. TEM images of Pt-SiPy+Cl− nanohybrid indicated an average size of 3–40 nm for PtNPs. The Pt-SiPy+Cl− was used as a polycation in the preparation of layer-by-layer films (LbL) on a glass substrate coated with fluorine-doped tin oxide (FTO) alternating with the polyanion poly(vinyl sulfonic acid) (PVS). The films were electrochemically tested in sulfuric acid to confirm the deposition of Pt-SiPy+Cl− onto the LbL films, observing the adsorption and desorption of hydrogen (E pa = 0.1 V) and by the redox process of formation for PtO with E pa = 1.3 V and E pc = 0.65 V. FTIR and Raman spectra confirmed the presence of the PVS and Pt-SiPy+Cl− in the LbL films. A linear increase in the absorbance in the UV–Vis spectra of the Pt-SiPy+Cl− at 258 nm (π → π* transition of the pyridine groups) with a number of Pt-SiPy+Cl−/PVS or PVS/SiPy+Cl− bilayers (R = 0.992) was observed. These LbL films were tested for the determination of dopamine (DA) in the presence of ascorbic acid (AA) with a detection limit (DL) on the order of 2.6 × 10−6 mol L−1 and a quantification limit (QL) of 8.6 × 10−6 mol L−1. The films exhibited a good repeatability and reproducibility, providing a potential difference of 550 mV for the oxidation of DA with AA interferent.

Production of Platinum Nanoparticles and Nanoaggregates Using Neurospora crassa

Fungal biomass and fungal extract of the nonpathogenic fungus Neurospora crassa were successfully used as reducing agents for the biosynthesis of platinum nanoparticles (PtNPs). The experiment was carried out by exposing the fungal biomass or the fungal extract to a 0.001 M precursor solution of hexachloroplatinic(IV) acid (H2PtCl6). A change of color of the biomass from pale yellow to dark brown was the first indication of possible formation of PtNPs by the fungus. Subsequent analyses confirmed the intracellular biosynthesis of single PtNPs (4-35 nm in diameter) and spherical nanoaggregates (20-110 nm in diameter). Using the fungal extract, similar results were obtained, producing rounded nanoaggregates of Pt single crystals in the range of 17-76 nm.

Anionically cross linked homopolymer colloids applied in formation of platinum nanoparticles

Diprotonic sulfuric and succinic acids react efficiently with the tertiary amine sites in polydimethylaminoethylmethacrylate (PDMAEMA) to produce polymer colloid nano-particles held together by dinegatively charged anions that cross link the partially protonated PDMAEMA homopolymer. This procedure is used to encorporate [PtCl6]2− as a cross linker into the framework of well defined polymer network colloid particles that have dual roles as nanoreactors and a source of protective polymer coating. Reduction of the cross linking [PtCl6]2− groups produces platinum metal nano-particles (1.12(.25)nm) that are relatively small and narrowly dispersed. Formation of colloid particles by reaction of diprotic acids with homopolymers that have proton accepting centers provides a convenient intentional route to incorporate a variety of homopolymers into self assembled polymer network materials for applications as nanoreactors and transport systems.

Preparation and Characterization of Platinum/Polyaniline Core-Shell Composite

Abstract. The core-shell composite of platinum/polyaniline (Pt@PAN) had been prepared by chemical synthesis approach. Reduction of the platinum salt in aqueous solution leaded to the formation of platinum nanoparticles, and then polyaniline were synthesized by interfacial polymerization to get Pt@PAN composite. Transmission electron microscopy of Pt@PAN showed Pt particles are uniform with spherical and granular morphology. Pt@PAN was also characterized by EDAX, XPS and FTIR.

A novel electroless method for the deposition of single-crystalline platinum nanoparticle films on an organic solid matrix in the presence of gold single crystals

Single-crystalline platinum nanoparticles (Pt-NPs) were directly deposited on and inside an organic solid matrix by a novel electroless galvanic method. The reducing agent was a solid phase confined with both a reducing agent and a stabilizer combined with initially deposited minute gold single crystals (Au-SCs) on the surface (Au-SM). The oxidizing agent (K2PtCl4) was in the aqueous solution phase. The reaction was carried out at the solid–liquid interface system at 80 °C and pH 1. The deposited Pt-NPs formed a uniform silver-grey conductive coating on the top of the Au-SM when the concentration of K2PtCl4 in the solution was 50 mM. The film consisted of single-crystalline Pt-NPs nearly identical in shape and size (∼250 nm). The initially deposited minute Au-SCs by the electroless deposition process were found to catalyze the formation of Pt-NPs having fcc crystal structures with dominating {111} crystal facets. The formation of Pt-NPs was not observed in the absence of initially deposited Au-SCs on the solid matrix. This method was also applicable for the deposition of deep ruby-red, optically transparent and mechanically stable Pt-NPs on and inside the Au-SM for lower concentrations of K2PtCl4 (1 to 5 mM) in the solution phase. This characteristic color was due to the strong surface plasmon absorption of Pt-NPs in the visible range. The Pt atoms initially deposited on the surface and diffused through the entire Au-SM to the opposite side that was not in contact with the oxidizing agent during the period of the reaction. The Pt-NPs on the solution-side of the Au-SM were partially naked and stabilized only from the bottom side, i.e., the upper sides of these nanocrystals were free from the stabilizer coating. The Au-SCs immobilized thiol-based epoxy resin was used as the Au-SM. The proposed Au-SM method was also applicable for the formation of ruby-red iron, palladium and beautiful, rainbow-like colorful silver nanoparticles on the Au-SM surface.