Synthesis Of Pt Nanoparticles Research Articles

One-step synthesis of platinum nanoparticles by pyrolysis of a polyplatinyne polymer

In this study, we report the synthesis and characterization of a new bis(pyridyl)-coordinated platinum(II)-containing metallopolyyne polymer. It is found that this metallopolymer can act as a precursor towards the synthesis of Pt nanoparticles upon pyrolysis (600 °C, 5 h). The resultant nanoparticles were characterized by transmission electron microscope (TEM), energy-dispersive X-ray analysis (EDXA) and powder X-ray diffraction (PXRD). The results verify that monodisperse Pt nanoparticles with defined morphology can be obtained. This pilot study reveals the potential of fabricating patterned Pt nanoparticles by using various lithographic methods in the future.

Synthesis of Platinum Nanoparticles by Reductive Crystallization Using Polyethyleneimine

AbstractSub‐10‐nm‐sized Pt nanoparticles were synthesized by reducing Pt ions with NaBH4, with the addition of polyethyleneimine (PEI) as a protective reagent. Well‐dispersed Pt nanoparticles with a narrow size distribution were successfully produced. When lowering the pH of the PEI solution, cubic and tetrahedral nanoparticles were observed, while at a higher pH, only spherical nanoparticles were produced. In addition, by selecting a suitable concentration of PEI, the protective reagent itself can reduce Pt ions to generate Pt nanoparticles with diameters in the range of 12.9–70.7 nm. This shows the potential of one‐pot synthesis of Pt nanoparticles by just adding Pt ions and PEI.

Defect-mediated synthesis of Pt nanoparticles uniformly anchored on partially-unzipped carbon nanofibers for electrochemical biosensing

Abstract Defect-mediated engineering has been proven as a novel and effective strategy to integrate two individual materials into a nanocomposite to boost the performance. In the present work, nanocomposite of partially-unzipped stacked-cup carbon nanofibers (PUSCNFs) decorated with platinum nanoparticles (Pt NPs) have been successfully synthesized through the defect-mediated formation method. Owing to the introduction of abundant structural defects during the chemical oxidation process, Pt NPs with an average diameter of 2–3 nm were uniformly anchored on the PUSCNFs without any surfactant involved. As comparison, the Pt NPs grown on the stacked-cup carbon nanofibers (SCNFs) possessed markedly larger nanoparticle size and trended to aggregate. The electrochemical properties of the nanocomposite-modified electrodes for biosensing were examined. Our results showed the Pt-PUSCNFs nanocomposite possessed optimal electrocatalytic activities and biosensing performance for detection of biomolecules, which could be attributed to a synergistic effect between the PUSCNFs and Pt NPs on electron transport and catalytic properties. We anticipate that the PUSCNFs may be a potential support material for construction of nanocomposites with good performance.

Biological synthesis of Pt nanoparticles in a microfluidic chip and modeling of the formation process withPBMandCFD

AbstractBACKGROUNDBiological synthesis of platinum nanoparticles (PtNPs) withCacumen platycladi(C. platycladi) in a microfluidic chip and numerical simulation of formation processes were studied. The effect of volumetric flow rate onPtNPs' size distribution was investigated in detail not only by experimental methods but also by means of numerical simulation. Computational fluid dynamics (CFD) and a population balance model (PBM) combined with reactive kinetics were employed to simulatePtNPs' formation and to calculate the particle size distributions (PSD).RESULTSThe experimental results confirmed the validity of the model and its practicality in predicting the formation ofPtNPsandPSDevolution in the microfluidic chip. In addition, the numerical simulation results also tested and verified the accuracy of the results and conclusions acquired from the experiment.CONCLUSIONIt is concluded thatPSDwas influenced not only by mixing efficiency but also by residence time in the microfluidic chip, and that the two factors were determined by volumetric flow rate. There is a specific volumetric flow rate to achieve equilibrium (optimal mixing and residence time) that results in the average particle size reaching its maximum value. This work provides useful insight into the microfluidic biological synthesis ofPtNPsand the influence of volumetric flow rate on size distribution in a microfluidic chip. © 2017 Society of Chemical Industry

Facile synthesis of Pt nanoparticles supported on anatase TiO2 nanotubes with good photo-electrocatalysis performance for methanol

A Pt/TNTs/C catalyst showed enhanced MOR performance under the light illumination.

Plasma-induced synthesis of Pt nanoparticles supported on TiO2 nanotubes for enhanced methanol electro-oxidation

A Pt/C/TiO2 nanotube composite catalyst was successfully prepared for enhanced methanol electro-oxidation. Pt nanoparticles with a particle size of 2nm were synthesized by plasma sputtering in water, and anatase TiO2 nanotubes with an inner diameter of approximately 100nm were prepared by a simple two-step anodization method and annealing process. Field-emission scanning electron microscopy images indicated that the different morphologies of TiO2 synthesized on the surface of Ti foils were dependent on the different anodization parameters. The electrochemical performance of Pt/C/TiO2 catalysts for methanol oxidation showed that TiO2 nanotubes were more suitable for use as Pt nanoparticle support materials than irregular TiO2 short nanorods due to their tubular morphology and better electronic conductivity. X-ray photoelectron spectroscopy characterization showed that the binding energies of the Pt 4f of the Pt/C/TiO2 nanotubes exhibited a slightly positive shift caused by the relatively strong interaction between Pt and the TiO2 nanotubes, which could mitigate the poisoning of the Pt catalyst by COads, and further enhance the electrocatalytic performance. Thus, the as-obtained Pt/C/TiO2 nanotubes composites may become a promising catalyst for methanol electro-oxidation.

Facile synthesis of Pt nanoparticles supported on graphene/Vulcan XC-72 carbon and their application for methanol oxidation

A facile method was used for the preparation of Pt nanoparticles supported on graphene/Vulcan XC-72 carbon (denoted as Pt/Gr-C) by co-reduction of graphene oxide (GO) and H2PtCl6 with subsequent incorporation of Vulcan XC-72 carbon between graphene. The catalyst is extensively characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. SEM and TEM observations show that aggregation of graphene is weakened through carbon insertion, which is beneficial for increase of effective contact area between catalyst and electrolyte. The electrochemical active surface area (ECSA) of Pt/Gr-C is higher than both Pt/C and Pt/Gr catalysts. The forward peak current density of Pt/Gr-C for methanol oxidation is 0.3 A mg−1 Pt, which is 1.4 and 1.7 times larger than Pt/Gr and Pt/C, respectively, due to the high utilization of Pt and large three-phase interface for methanol oxidation.

Synthesis of Pt nanoparticles with preferential (1 0 0) orientation directly on the carbon support for Direct Ethanol Fuel Cell

The synthesis of Pt nanoparticles with preferential (100) orientation directly supported on carbon was done by an alcohol-reduction process using KBr as a shape directing agent. The synthesis conditions were varied and the obtained materials were characterized by transmission electron microscopy and cyclic voltammetry. The order of addition of the Pt precursor and KBr was crucial to obtain cubic Pt nanoparticles with small particle size highly dispersed on the carbon support. DEFC experiments showed that Pt nanoparticles with preferential (100) orientation supported on carbon provided superior power densities and CO2 selectivity compared to supported polycrystalline Pt nanoparticles.

Graphite-specific peptide mediated synthesis of Pt nanoparticles on reduced graphene oxide for electrochemical detection of H2O2

We demonstrate here a facile and effective strategy to prepare reduced graphene oxide-platinum nanoparticle (RGO-PtNP) nanohybrids by the mediation of graphite-specific peptide (GSP). For the first time, we found that GSP can be used to modify RGO non-covalently in one way, and in another way promote the formation of PtNPs on RGO as a biomolecular bridge. The created RGO-PtNP nanohybrids show enhanced electrocatalytic activity toward H2O2 and can be utilized to fabricate non-enzymatic electrochemical H2O2 sensor.

Pt nanoparticles embedded on reduced graphite oxide with excellent electrocatalytic properties

Economically viable electrochemical approach has been developed for the synthesis of Pt nanoparticles through electrodeposition technique on the surface of Reduced Graphite Oxide (RGO). Pt nanoparticles embedded Reduced Graphite Oxide on Glassy Carbon Electrode are employed (Pt-rGO/GCE) for electrooxidation of formic acid. Scanning Electron Microscopy (SEM) image and Transmission Electron Microscopy (TEM) image shows that reduced graphite oxide act as an excellent support to anchor the Pt nanoparticles. Cyclic voltammetry results confirmed that Pt-rGO/GCE enhanced current density as many folds than that of bare platinum electrode for electrooxidation of formic acid. X-ray diffraction (XRD) patterns for Pt-graphene composites illustrate that peaks at 69.15 and 23° for Pt (220) and graphene carbon (002) respectively. 13C NMR spectrum of the electrochemically reduced graphite oxide resonance contains only one peak at 133ppm which retains graphitic sp2 carbon and does not contain any oxygenated carbon and the carbonyl carbons.

Atomic Layer Deposition of Pt Nanoparticles within the Cages of MIL-101: A Mild and Recyclable Hydrogenation Catalyst.

We present the in situ synthesis of Pt nanoparticles within MIL-101-Cr (MIL = Materials Institute Lavoisier) by means of atomic layer deposition (ALD). The obtained Pt@MIL-101 materials were characterized by means of N2 adsorption and X-ray powder diffraction (XRPD) measurements, showing that the structure of the metal organic framework was well preserved during the ALD deposition. X-ray fluorescence (XRF) and transmission electron microscopy (TEM) analysis confirmed the deposition of highly dispersed Pt nanoparticles with sizes determined by the MIL-101-Cr pore sizes and with an increased Pt loading for an increasing number of ALD cycles. The Pt@MIL-101 material was examined as catalyst in the hydrogenation of different linear and cyclic olefins at room temperature, showing full conversion for each substrate. Moreover, even under solvent free conditions, full conversion of the substrate was observed. A high concentration test has been performed showing that the Pt@MIL-101 is stable for a long reaction time without loss of activity, crystallinity and with very low Pt leaching.

Facile synthesis of Pt nanoparticles loaded porous graphene towards oxygen reduction reaction

A facile method was developed to fabricate Pt nanoparticles loaded porous graphene (Pt-PGR) composites via impregnation and reduction. The PGR was first immersed into a H2PtCl6 ethanol solution, and then the H2PtCl6 was reduced to Pt nanoparticles with NaBH4 to produce the Pt-PGR composites. Morphologies and composition of the Pt-PGR composites were characterized by filed-emission scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and nitrogen physisorption. It was found that the obtained Pt-PGR composites had three-dimensional interpenetrating porous structure, and the Pt nanoparticles from 50 to 150nm uniformly distributed on the graphene surfaces. Electrochemical and electrocatalytical properties of the Pt-PGR composite were investigated by cyclic voltammogram and linear sweep voltammogram. The results indicated that the Pt-PGR composites had excellent catalytical activity towards the oxygen reduction reaction (ORR), and showed the higher diffusion-limited current densities (4.0mAcm−2 and 25mAmgpt−1 at −0.6V) and stability compared with the commercial 20% Pt/C catalyst. The electrocatalytical kinetics experiments showed that the electron transfer number was 3.6 calculated from the Koutecky-Levich plot, indicating an approximate four-electron process and the oxygen directly reduced to water for the ORR.

Polyoxometalates-mediated facile synthesis of Pt nanoparticles anchored on an ordered mesoporous carbon for electrochemical applications

A green and facile strategy to develop electrochemical sensors through the rational design of platinum nanoparticles@polyoxometalate decorating ordered mesoporous carbon (Pt@POMs-OMC) nanohybrids.

Novel synthesis of chitosan protected platinum nanoparticles based on gas–liquid interfacial reactions and their application for electrochemical sensing of hydrogen peroxide

A gas–liquid reaction was proposed for the controllable synthesis of Pt nanoparticles, which exhibited uniform morphology without any aggregation.

Synthesis of Nanostructured Catalytic Materials from Microemulsions

Since the 1980s [1,2], colloidal systems such as microemulsions (ME) have been widely investigated, especially for the synthesis of nanomaterials for various applications.[...]

A Study on Reactive Spray Deposition Technology Processing Parameters in the Context of Pt Nanoparticle Formation

Catalytic materials are complex systems in which achieving the desired properties (i.e., activity, selectivity and stability) depends on exploiting the many degrees of freedom in surface and bulk composition, geometry, and defects. Flame aerosol synthesis is a process for producing nanoparticles with ample processing parameter space to tune the desired properties. Flame dynamics inside the reactor are determined by the input process variables such as solubility of precursor in the fuel; solvent boiling point; reactant flow rate and concentration; flow rates of air, fuel and the carrier gas; and the burner geometry. In this study, the processing parameters for reactive spray deposition technology, a flame-based synthesis method, are systematically evaluated to understand the residence times, reactant mixing, and temperature profiles of flames used in the synthesis of Pt nanoparticles. This provides a framework for further study and modeling. The flame temperature and length are also studied as a function of O2 and fuel flow rates.

A dispenser-reactor apparatus applied for in situ XAS monitoring of Pt nanoparticle formation.

In situ time-resolved X-ray absorption spectroscopy (XAS) measurements collected at the Pt L3-edge during the synthesis of Pt nanoparticles (NPs) in aqueous solution are reported. A specially designed dispenser-reactor apparatus allowed for monitoring changes in the XAS spectra from the earliest moments of Pt ions in solution until the formation of metallic nanoparticles with a mean diameter of 4.9 ± 1.1 nm. By monitoring the changes in the local chemical environment of the Pt atoms in real time, it was possible to observe that the NPs formation kinetics involved two stages: a reduction-nucleation burst followed by a slow growth and stabilization of NPs. Subsequently, the synthesized Pt NPs were supported on activated carbon and characterized by synchrotron-radiation-excited X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and extended X-ray absorption fine structure (EXAFS). The supported Pt NPs remained in the metallic chemical state and with a reduced size, presenting slight lattice parameter contraction in comparison with the bulk Pt values.

Pt Nanoparticles via Oil-in-Water Microemulsions Stabilized by a Technical Grade Surfactant: An Economical and Ecological Approach

Abstract This study deals with the synthesis of Pt nanoparticles via oil-in-water microemulsions formulated with the technical grade surfactant BIODAC® 510. For this purpose we studied the influence of the Platinum precursor dimethyl(cyclooctadiene)platinum (Pt(COD)Me2) on the phase behavior of the base microemulsion. It was found that the addition of Pt(COD)Me2 has nearly no effect on the phase boundaries even at relatively high concentrations. Small angle X-ray scattering data confirmed that the addition of the metal organyl also does not influence the size of the microemulsion droplets. According to transmission electron microscopy (TEM) the size of the resulting platinum nanoparticles is independent on the amount of Pt(COD)Me2 in the templating microemulsion. This result was rather surprising since it indicates that a greater amount of precursor in the o/w-microemulsion leads to more rather than to larger nanoparticles.

A Review on Chemical Synthesis Process of Platinum Nanoparticles

Nanoparticles are key components in the advancement of future energy technologies; thus, strategies for preparing nanoparticles in large volume by techniques that are cost-effective are required. In the substitution of fossil-fuels by renewable energy resources, nanometersized particles play a key role for synthesizing energy vectors from varying and heterogeneous biomass feedstocks. They are extensively used in reformers for the production of hydrogen from solid, liquid, or gaseous energy carriers. Catalyst activities depend critically on their size-dependent properties. Nanoparticles are further indispensable as electrocatalysts in fuel cells and other electrochemical converters. The desire to increase the activity per unit area, and decrease the necessary amount of the expensive catalytic standard, It is clear that performance and commercialization of fuel cells depend on electrode materials performance. The application of pt nanomaterials as an electrode in the field of fuel cell has become a new, growing area of interest in recent years. We review chemical process for synthesis of pt nanoparticles. Recent developments in syntheses process of pure & mixed platinum nanoparticles has briefly reviewed specifically for applications in fuel cells. As the physicochemical properties of noble-metal nanostructures are strongly dependent upon shape and size, the development of reliable synthesis methods for the production of nanocrystals with well-defined size and morphology have been discussed briefly. The role of nanostructured supports for the nanoparticles, such as ordered mesoporous carbon, dendrimer have also discussed. And size of the nanoparticles obtained in deferent process and their temperature dependence has also discussed briefly.

One-step Synthesis of Pt Nanoparticles Highly Loaded on Graphene Aerogel as Durable Oxygen Reduction Electrocatalyst

Synthesis of highly active and durable Pt based catalysts with a high metal loading for fuel cells’ applications still remains a big challenge. The three-dimensional (3D) graphene aerogel (GA) not only possess the intrinsic property of graphene, but also have abundant pore architecture for anchoring metal nanoparticles, thus would be suitable as metal catalysts’ support. This work reports a simple and mild one-step co-reduction synthesis of Pt nanoparticles highly loaded on 3D GA and the use as durable oxygen reduction catalyst. Both X-ray diffraction and TEM measurements confirm that Pt nanoparticles (ca. 60wt.% Pt loading) with an average diameter of ca. 3.2nm are uniformly decorated on the homogeneously interconnected pores of 3D GA even after a heat treatment at 300°C. Such a Pt/GA catalyst exhibits significantly enhanced electrocatalytic activity and improved durability for the oxygen reduction reaction. The enhancement in both catalytic activity and durability may result from the unique 3-D architecture structure of GA, the uniform dispersion of Pt nanoparticles, and the interaction between the Pt nanoparticles and GA. The GA-supported Pt can serve as a highly active catalyst for fuel cell applications.