Metallic Nanoparticles from Single Polyelectrolyte Molecules

2002 ◽  
Vol 726 ◽  
Author(s):  
Ganna Gorodyska ◽  
Anton Kiriy ◽  
Sergiy Minko ◽  
Manfred Stamm
Keyword(s):  
Metallic Nanoparticles ◽  
Flat Surface ◽  
Pd Nanoparticles ◽  
Palladium Acetate ◽  
Step Procedure ◽  
Synthetic Procedure ◽  
Metallic Palladium ◽  
Dimethylamine Borane ◽  
Pd Clusters ◽  
Si Wafer

AbstractHere we report on the metallization of poly(2-vinylpyridine) (P2VP) by coordination with palladium acetate (PA) followed by reduction with dimethylamine borane (DAB) to metallic palladium. The morphology of the resulting products deposited on a flat surface was analyzed with AFM. If P2VP, PA and DAB are mixed together, the Pd clusters up to 30 nm in diameter are obtained. A two step synthetic procedure was examined. The initially prepared complex P2VPH-1/2(PdCl4) was deposited on Si-wafer and then reduced, leading to the Pd clusters with a narrow size distribution (3 nm height by 100 nm length). Alternately, a step-by-step procedure was used wherein P2VP single molecules were deposited on Si wafers from very dilute acidic aqueous solutions then placed in PA solution and finally reduced with DAB, resulting in the 1.5-5 nm in the diameter wire-shaped Pd nanoparticles with the length of about 350 nm.

Non-Equilibrium Properties of Au-Pd Nanoparticles

2011 ◽  
Vol 172-174 ◽  
pp. 670-675 ◽  
Author(s):  
Ivailo S. Atanasov ◽  
Marc Hou
Keyword(s):  
Molecular Dynamics ◽  
Low Temperatures ◽  
Pd Nanoparticles ◽  
Core Shell ◽  
Embedded Atom ◽  
Cluster Morphology ◽  
Pd Clusters ◽  
Atom Potential ◽  
The Way

We address the question of the evolution of a nanostructured system in a metastable state to equilibrium. To this purpose, we use the case study of the transition of an AucorePdshell nanoalloy cluster containing up to about 600 atoms toward the equilibrium Au segregated configuration. We start from a molecular dynamics approach with an embedded atom potential. The way the transition develops at low temperatures is found to be very sensitive to the cluster morphology and the way energy is exchanged with the environment. The transition of icosahedral inverse core-shell Au-Pd clusters is predicted to nucleate locally at the surface contrary to clusters with other morphologies, and starting at lower temperatures compared to them.

CHANGES OF RIPPLE MORPHOLOGY OF CLEAVED Si SURFACE BY LOW-ENERGY Ar+ ION BEAM SPUTTERING

2011 ◽  
Vol 10 (03) ◽  
pp. 495-499 ◽  
Author(s):  
S. A. PAHLOVY ◽  
S. F. MAHMUD ◽  
K. YANAGIMOTO ◽  
I. MIYAMOTO
Keyword(s):  
Wave Vector ◽  
Flat Surface ◽  
Incidence Angle ◽  
Ion Beam ◽  
Wave Length ◽  
Ion Beam Sputtering ◽  
Smooth Plane ◽  
Beam Sputtering ◽  
Atomically Flat ◽  
Si Wafer

We have investigated the changes of ripple morphology of an atomically flat cleaved Si surface due to Ar+ ion bombardment. The cleaved atomically flat and smooth plane of Si wafer was obtained by cutting vertically against the orientation flat of a Si (100) wafer. Then, the cleaved surface was bombarded by 1 keV Ar+ ion beam at ion incidence angle of 0°, 50°, 60°, 70°, and 80°. The ripples structure were depends on ion dose and angle formed on atomically flat surface at ion incidence angle of 50°, 60°, 70°, and 80°. Ripples were unclear and small at ion doses of 1.0 × 1018 ions/cm2 but pronounced at ion dose of 8.0 × 1018 ions/cm2. The wave lengths of ripples were measured and the maximum wave length is 425 nm at ion incidence angle of 70° and ion dose of 8.0 × 1018 ions/cm2. Results show that the wave length of ripple depends on ion doses and angle of ion incidence. It was also observed that the wave vector of ripple changes with changing the angle of ion incidence. This research is concluded by discussing the wave vector changing mechanism with the help of BH model.

scholarly journals Green synthesis of Ag and Pd nanoparticles for water pollutants treatment

2020 ◽  
Vol 82 (11) ◽  
pp. 2344-2352
Author(s):  
C. Joseph Kirubaharan ◽  
Zhen Fang ◽  
Chong Sha ◽  
Yang-Chun Yong
Keyword(s):  
Green Synthesis ◽  
Metallic Nanoparticles ◽  
Rhodamine 6G ◽  
Catalytic Efficiency ◽  
Pd Nanoparticles ◽  
Antibacterial Activities ◽  
Klebsiella Pneumonia ◽  
Vibrio Cholera ◽  
Structural Nature ◽  
Ft Ir

Abstract Silver (Ag) and palladium (Pd) nanoparticles were synthesized via a green synthesis route, which was mediated with the extract of Daucus carota leaves. The morphological, crystalline and structural nature of the synthesized nanoparticles was characterized by UV-Vis spectrophotometer, and TEM, XRD and FT-IR analyses. High antibacterial activities of the prepared Ag and Pd nanoparticles were observed towards different water-borne pathogens of Klebsiella pneumonia, Vibrio cholera and Escherichia coli. The catalytic efficiency of the prepared nanoparticles for the removal of rhodamine 6G (Rh-6G) dye was also evaluated. Nearly 98% of the Rh-6G dye was decolorized by the synthesized Pd nanoparticles within 2 min, and the synthesized Ag nanoparticles took 30 min for 89.4% decolorization. This work provided greener nanocatalysts for pollutant treatment and demonstrated the power of green biosynthesis for metallic nanoparticles.

scholarly journals Sonochemical Deposition of Palladium Nanoparticles Onto the Surface of N-Doped Carbon Nanotubes: A Simplified One-Step Catalyst Production Method

2019 ◽  
Vol 150 (2) ◽  
pp. 505-513
Author(s):  
Ádám Prekob ◽  
Gábor Muránszky ◽  
István Kocserha ◽  
Béla Fiser ◽  
Ferenc Kristály ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Reaction Rate ◽  
Pd Nanoparticles ◽  
Production Method ◽  
Sonochemical Method ◽  
Nitrobenzene Hydrogenation ◽  
Step Procedure ◽  
One Step ◽  
Catalyst Production ◽  
Nitrogen Doped Carbon

Abstract This work presents an easy, one-step procedure for catalyst preparation. A small fraction of palladium ions was reduced to Pd nanoparticles and deposited onto the surface of nitrogen-doped carbon nanotubes (N-BCNT) by acoustic cavitation using high-intensity ultrasound in aqueous phase, where N-BCNT served as a reducing agent. The formation of elemental palladium and palladium oxides were confirmed and the particle size is < 5 nm. The catalytic activity of the synthesized Pd/N-BCNT catalyst was tested in nitrobenzene hydrogenation at four different temperature (273–323 K) and 20 bar pressure. The catalyst showed high activity despite the presence of palladium oxide forms, the conversion of nitrobenzene to aniline was 98% at 323 K temperature after 40 min. The activation energy was 35.81 kJ/mol. At 303 K and 323 K temperature, N-methylaniline was formed as by-product in a small quantity (8 mmol/dm3). By decreasing the reaction temperature (at 273 K and 283 K), the reaction rate was also lower, but it was favourable for aniline selectivity, and not formed n-methylaniline. All in all, Pd/N-BCNT catalyst was successfully produced by using a one-step sonochemical method, where further activation was not necessary as the catalytic system was applicable in nitrobenzene hydrogenation. Graphic Abstract

Palladium Acetate and Pd Nanoparticles Loaded Hexamethylenetetramine Anchored Magnetically Retrievable Assemblies for Catalyzing Mizoroki‐Heck Type Mono and Gem ‐Dicoupling Reactions

2020 ◽  
Vol 5 (6) ◽  
pp. 1961-1971
Author(s):  
Prakash B. Rathod ◽  
K. S. Ajish Kumar ◽  
Mukesh Kumar ◽  
A. K. Debnath ◽  
Ashok K. Pandey ◽  
...  
Keyword(s):  
Pd Nanoparticles ◽  
Palladium Acetate

scholarly journals Supported Palladium Nanocatalysts: Recent Findings in Hydrogenation Reactions

Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1172
Author(s):  
Marta A. Andrade ◽  
Luísa M. D. R. S. Martins
Keyword(s):  
Metallic Nanoparticles ◽  
Pd Nanoparticles ◽  
Solid Supports ◽  
Research Areas ◽  
Wide Range ◽  
Palladium Nanocatalysts ◽  
Recent Developments ◽  
Hydrogenation Reactions ◽  
Metal Organic ◽  
Major Factors

Catalysis has witnessed a dramatic increase on the use of metallic nanoparticles in the last decade, opening endless opportunities in a wide range of research areas. As one of the most investigated catalysts in organic synthesis, palladium finds numerous applications being of significant relevance in industrial hydrogenation reactions. The immobilization of Pd nanoparticles in porous solid supports offers great advantages in heterogeneous catalysis, allowing control of the major factors that influence activity and selectivity. The present review deals with recent developments in the preparation and applications of immobilized Pd nanoparticles on solid supports as catalysts for hydrogenation reactions, aiming to give an insight on the key factors that contribute to enhanced activity and selectivity. The application of mesoporous silicas, carbonaceous materials, zeolites, and metal organic frameworks (MOFs) as supports for palladium nanoparticles is addressed.

scholarly journals Organotrialkoxysilane-Functionalized Noble Metal Monometallic, Bimetallic, and Trimetallic Nanoparticle Mediated Non-Enzymatic Sensing of Glucose by Resonance Rayleigh Scattering

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 122
Author(s):  
Prem C. Pandey ◽  
Murli Dhar Mitra ◽  
Shubhangi Shukla ◽  
Roger J Narayan
Keyword(s):  
Metal Nanoparticles ◽  
Noble Metal ◽  
Metallic Nanoparticles ◽  
Rayleigh Scattering ◽  
Metal Cations ◽  
Pd Nanoparticles ◽  
Glucose Sensing ◽  
Noble Metal Nanoparticles ◽  
Resonance Rayleigh Scattering ◽  
Gold Silver

Organotrialkoxysilanes like 3-aminopropyltrimethoxysilane (3-APTMS)-treated noble metal cations were rapidly converted into their respective nanoparticles in the presence of 3-glycidoxypropylytrimethoxysilane (3-GPTMS). The micellar activity of 3-APTMS also allowed us to replace 3-GPTMS with other suitable organic reagents (e.g., formaldehyde); this approach has significant advantages for preparing bimetallic and trimetallic analogs of noble metal nanoparticles that display efficient activity in many practical applications. The formation of monometallic gold, silver, and palladium nanoparticles, bimetallic Ag-Pd, and Au-Pd nanoparticles at various ratios of noble metal cations, and trimetallic Ag-Au-Pd nanoparticles were studied; their biocatalytic activity in non-enzymatic sensing of glucose based on monitoring synchronous fluorescence spectroscopy (SFS) was assessed. Of these nanoparticles, Au-Pd made with an 80:20 Au:Pd ratio displayed excellent catalytic activity for glucose sensing. These nanoparticles could also be homogenized with Nafion to enhance the resonance Rayleigh scattering (RRS) signal. In this study, the structural characterization of noble metal nanoparticles as well as bi- and tri-metallic nanoparticles in addition to their use in non-enzymatic sensing of glucose are reported.

scholarly journals Size-dependent non-space filling atomic packing in metallic nanoparticles

2014 ◽  
Vol 70 (a1) ◽  
pp. C867-C867
Author(s):  
Vicky Doan-Nguyen ◽  
Simon Kimber ◽  
Diego Pontoni ◽  
Danielle Reifsnyder ◽  
Benjamin Diroll ◽  
...  
Keyword(s):  
Metallic Nanoparticles ◽  
Pd Nanoparticles ◽  
Distribution Functions ◽  
Face Centered Cubic ◽  
Structure Property ◽  
Space Filling ◽  
Atomic Packing ◽  
Size Dependent ◽  
Local Ordering ◽  
Icosahedral Clusters

Ni-Pd nanoparticles synthesized for CO catalysis are characterized by transmission electron microscopy and total X-ray scattering. The sizes of these nanoparticles can be tuned to size with great control over the monodispersity of the samples. The pair distribution functions of the reveal a local ordering within the highly disordered atomic structure within the nanoparticles. The PDFs show a size-dependent deviation from typical bulk face centered cubic (fcc) structure for these materials. The long-range isotropic disorder within these non-fcc nanoparticles can be fitted using an exponentially damped single-mode sine wave. Below a diameter of 5 nm, the Ni-Pd nanoparticles exhibit local ordering of atoms as found in typical icosahedral clusters. The transition from fcc to non-space filling atomic packing of icosahedral clusters in a nanoparticle is modeled to show the structural origin of the observed PDFs. Understanding this type of disorder can give insight into structure-property relations for applications in heterogeneous catalysis.

scholarly journals Nanometric morpho-structural characterization of mesoporous metal oxide semiconductors for chemo-resistive gas sensors

2019 ◽  
Vol 1 (1) ◽  
pp. 34-35
Keyword(s):  
Gas Sensors ◽  
Metallic Nanoparticles ◽  
Gas Sensing ◽  
Analytical Electron Microscopy ◽  
Experimental Conditions ◽  
Nano Structure ◽  
Sensing Properties ◽  
Gas Sensing Properties ◽  
Pd Clusters ◽  
Mesoporous Sno2

SnO2 and ZnO are among the most studied semiconductor oxides for applications as gas sensing devices for detecting and monitoring the presence of toxic gases such as CO, NO, NO2. Enhanced sensing properties have been recently reported on gas sensor based on SnO2-ZnO composites due to the formation of hetero-junction between ZnO and SnO2 grains and the contribution of a depleted layer at the intergrain ZnO-SnO2 interfaces. The sensing characteristics can be further improved by adding metallic nanoparticles with a catalytic activity, like Pt or Pd. Along with the electrical properties of such a complex system, morphology plays an essential role in facilitating and enhancing the interaction with the surrounding gas. In our work, ZnO doped SnO2 mesoporous system for gas sensors has been prepared using solvothermal methods in various experimental conditions. Aiming for a proper optimization of the gas sensing properties, the above mentioned system has been decorated with Pd using wet spray method. This work presents an in depth structural and morphological study by combined techniques of analytical electron microscopy on the mesoporous SnO2-ZnO systems decorated with Pd in function of the synthesis conditions. Electron tomography has been employed for a complete, 3D investigation of the Pd clusters distribution within the mesoporous SnO2-ZnO matrix. By a proper image segmentation Pd clusters have been successfully isolated in the surrounding ZnO-doped SnO2 matrix, thus allowing more complex correlations between the micro/nano-structure and the gas sensing properties.

scholarly journals A Comparison of Pd0 Nanoparticles and Pd2+ Modified Bi2O2CO3 for Visible Light-Driven Photocatalysis

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Xiangchao Meng ◽  
Zizhen Li ◽  
Nan Yun ◽  
Zisheng Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Palladium Nanoparticles ◽  
Metallic Nanoparticles ◽  
Pd Nanoparticles ◽  
Absorption Capacity ◽  
Visible Light Absorption ◽  
Ion Doping ◽  
Visible Light Driven ◽  
Photocatalytic Reactions

As two effective approaches to increase the visible light-absorption capacities of photocatalysts, ion doping and metallic nanoparticles loading are compared in this work. Palladium was selected to modify Bi2O2CO3. Compared to dispersing palladium nanoparticles on the photocatalyst surface, it was more effective for the method of doping with palladium to shift the energy level within the bandgap of Bi2O2CO3 in improving its photocatalytic activity under visible light. This might be because doping with Pd2+ narrows the band gap of Bi2O2CO3 so as to increase the absorption capacity of visible light photons. Pd nanoparticles on the other hand can absorb photons to produce electrons which are then utilized by Bi2O2CO3 for photocatalytic reactions. Different mechanisms resulted in significant differences, and this work provides solid evidence that ion doping may be a more effective method to improve the photocatalytic activity of Bi2O2CO3.

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