Influence of Ethanol Catalyzed Oxidation on the Activity of Pd/C with Different Ratio of Pd and Carbon

2013 ◽  
Vol 860-863 ◽  
pp. 835-838
Author(s):  
Zhong Xu Dai ◽  
Dan Ni Tian ◽  
Xin Zhang ◽  
Si Lin Gong ◽  
Chang Ying Yang
Keyword(s):  
Ethanol Oxidation ◽  
Chemical Reduction ◽  
Average Particle Size ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Face Centered ◽  
Catalyzed Oxidation ◽  
Better Than

To investigate the influence of ethanol catalyzed oxidation on activity of Pd/C with different ratio of Pd and C. Pd/C catalyst samples with Pd loads of 20, 30, 40 and 50 wt% were obtained by chemical reduction reaction of PdCl2 and NaBH4. The samples morphology and structure were characterized by XRD and SEM. The electrocatalytic oxidation activities of ethanol were examined by cyclic voltammetry in alkaline media. The results show that a face centered cubic (FCC) Pd phase can be identified in the sample powders. The average particle size of the Pd/C powder is about 10 nm. The performance of ethanol oxidation on 40 % Pd/C electro-catalyst is better than that of the other Pd/C samples.

Simple One-Step Synthesis of Uniform Disperse Copper Nanoparticles

2005 ◽  
Vol 879 ◽  
Author(s):  
Chunwei Wu ◽  
Brian P. Mosher ◽  
Taofang Zeng
Keyword(s):  
Ascorbic Acid ◽  
Copper Nanoparticles ◽  
Chemical Reduction ◽  
Average Particle Size ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Chemical Reduction Method ◽  
Disperse Copper ◽  
One Step ◽  
Face Centered

AbstractIn this paper, we describe a simple and rapid solution-phase chemical reduction method with no inert gas protection, for preparing stable copper nanoparticle colloid with average particle size of 3.4 nm and narrow size distribution. In our synthesis route, ascorbic acid, natural vitamin C (VC), serves as both a reducing agent and an antioxidant to reduce copper salt precursor and effectively prevent the general oxidation process occurring to the newborn nanoparticles. XRD and UV/vis confirm the formation of pure face-centered cubic (fcc) copper nanoparticles and the excellent antioxidant ability of ascorbic acid.

Microstructure Characterization of Ag Nanoparticles Prepared by Hydrothermal Method

2012 ◽  
Vol 476-478 ◽  
pp. 1138-1141
Author(s):  
Zhi Qiang Wei ◽  
Qiang Wei ◽  
Li Gang Liu ◽  
Hua Yang ◽  
Xiao Juan Wu
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Hydrothermal Method ◽  
Ag Nanoparticles ◽  
Average Particle Size ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Face Centered

Ag nanoparticles were successfully synthesized by hydrothermal method under the polyol system combined with traces of sodium chloride, Silver nitrate(AgNO3) and polyvinylpyrrolidone (PVP) acted as the silver source and dispersant respectively. The samples by this process were characterized via X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET) adsorption equation, transmission electron microscopy (TEM) and the corresponding selected area electron diffraction (SAED) to determine the chemical composition, particle size, crystal structure and morphology. The experiment results indicate that the crystal structure of the samples is face centered cubic (FCC) structure as same as the bulk materials, The specific surface area is 24 m2/g, the particle size distribution ranging from10 to 50 nm, with an average particle size about 26 nm obtained by TEM and confirmed by XRD and BET results.

scholarly journals Synthesis of Nanocrystalline Cellulose Stabilized Copper Nanoparticles

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Aminu Musa ◽  
Mansor B. Ahmad ◽  
Mohd Zobir Hussein ◽  
Saiman Mohd Izham ◽  
Kamyar Shameli ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Copper Nanoparticles ◽  
Metal Ion ◽  
Copper Ions ◽  
Chemical Reduction ◽  
Average Particle Size ◽  
Nanocrystalline Cellulose ◽  
Average Particle ◽  
Face Centered Cubic ◽  
X Ray

A chemical reduction method was employed for the synthesis of copper nanoparticles stabilized by nanocrystalline cellulose (NCC) using different concentrations of copper salt in aqueous solution under atmospheric air. CuSO4·5H2O salt and hydrazine were used as metal ion precursor and reducing agent, respectively. Ascorbic acid and aqueous NaOH were also used as an antioxidant and a pH moderator, respectively. The number of CuNPs increased with increasing concentration of the precursor salt. The formation of copper nanoparticles stabilized by NCC (CuNPs@NCC) was investigated by UV-visible spectroscopy (UV-vis), where the surface absorption maximum was observed at 590 nm. X-ray diffraction (XRD) analysis showed that the CuNPs@NCC are of a face-centered cubic structure. Moreover, the morphology of the CuNPs@NCC was investigated using transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM), which showed well-dispersed CuNPs with an average particle size less than 4 nm and the shape of CuNPs was found to be spherical. Energy dispersive X-ray spectroscope (EDS) also confirmed the presence of CuNPs on the NCC. The results demonstrate that the stability of CuNPs decreases with an increasing concentration of the copper ions.

scholarly journals THE GREEN SYNTHESIS OF SILVER NANOPARTICLES OF ONION DNA AND SCREENING FOR IN VITRO ANTITYROSINASE ACTIVITY

2019 ◽  
pp. 271-275
Author(s):  
SNEHA THAKUR ◽  
KRISHNA MOHAN G
Keyword(s):  
Silver Nanoparticles ◽  
Nitrate Solution ◽  
Average Particle Size ◽  
Research Work ◽  
Local Market ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Antityrosinase Activity ◽  
Cubic Structure ◽  
Face Centered

Objective: The main objective of the research work is to evaluate the antityrosinase potential of onion DNA silver nanoparticles (AgNPs). Methods: The onions were procured from the local market and DNA was extracted from onions using detergent and methylated spirit. The isolated DNA was selected for synthesis of AgNPs which acts as capping and reducing agent. About 10 ml of the DNA extract was added to 90 ml of 0.1 N silver nitrate solution. After 24 h incubation, the solution turned dark brown, which indicates the formation of AgNPs. The synthesized DNA AgNPs were characterized by ultraviolet-visible, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and dynamic light scattering (DLS) studies. Results: The results revealed that the particles were uniform in shape with face-centered cubic structure. The particles are 153±20.4 nm in size and were no signs of agglomeration measured by DLS studies. The FTIR spectroscopy revealed B form of DNA along with strong N-H stretching, C=N stretching, and also asymmetric vibrations of phosphate groups characteristic for DNA molecule. The XRD studies revealed the face-centered cubic structure. SEM studies revealed the spherical structure with average particle size of 150±0.1 nm for single DNA nanoparticles. The onion DNA AgNPs were further investigated for its antityrosinase activity against the standard kojic acid and were to have anticancer potential nearer to the standard. Conclusion: From the results, it is evident that the synthesized onion DNA AgNPs have antityrosinase potential and can be further investigated for in vivo anticancer potential in future.

Study on Nickel Nanopowders Prepared by Arc Plasma

2013 ◽  
Vol 734-737 ◽  
pp. 1555-1558
Author(s):  
Cong Hua Hou ◽  
Yun Ge Chen
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Barometric Pressure ◽  
Constant Current ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Arc Plasma ◽  
X Ray Diffraction ◽  
Current Voltage ◽  
Face Centered

In order to prepare the nickel nano-metal with high purity and uniform particle size , the arc plasma method was used. The nano-Ni was got under a constant current , voltage , barometric pressure, hydrogen and argon gas . The nickel nanopowders were tested through the Scan Electron Microscope (SEM ), X-ray diffraction (XRD), Laser Sizer Analysis (LSA). The results indicated that the feature of the nickel nanopowders were mainly spherical, smooth surface. The nickel powder particle distribute from 40 to 80nm. And average particle size is 60nm. Nanocrystals had a better internal crystallinity. The crystal structure is face-centered cubic FCC structure, the same as ordinary nickel nanoparticles .

Synthesis of CdS Nanoparticles by Sonochemical Reaction Using Thioasetamide as S2− Reservoir and in the Presence of a Neutral Surfactant, Dyeing of Cotton Fabric and Study of Antibacterial Effect on Cotton Fabric

2012 ◽  
Vol 622-623 ◽  
pp. 851-854 ◽  
Author(s):  
Masoumeh Tabatabaee ◽  
Paria Baziari ◽  
Navid Nasirizadeh ◽  
Hamed Dehghanizadeh
Keyword(s):  
Antibacterial Activity ◽  
Cotton Fabric ◽  
Average Particle Size ◽  
Cds Nanoparticles ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Simple Method ◽  
E Coli ◽  
Sonochemical Reaction ◽  
Face Centered

Nano-sized cadmium sulfid (CdS) was synthesized successfully by a simple method using ultrasonic irradiation in the presence of polyethylene glycol (PEG 2000). X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize the structure and morphology synthesized powder. The nanocrystaline of β-CdS was grown in face-centered cubic. The average particle size of synthesized CdS is ~25 nm. CdS suspensions have then been impregnated on cotton-based textile samples and the antibacterial activity of so-functionalized textiles has been studied with respect to E. coli. Results shows that CdS nanoparticles exhibit a strong antibacterial activity and can inhibit 97% of growth E. coli bacteria.

scholarly journals BIOREDUCTION AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM OIL PALM EMPTY FRUIT BUNCH

2020 ◽  
Vol 21 (4) ◽  
pp. 177
Author(s):  
Siti Suhartati ◽  
Iwan Syahjoko Saputra ◽  
Dwinna Rahmi ◽  
Yoki Yulizar ◽  
Sudirman Sudirman
Keyword(s):  
Silver Nanoparticles ◽  
Oil Palm ◽  
Average Particle Size ◽  
Average Particle ◽  
Face Centered Cubic ◽  
Empty Fruit Bunch ◽  
The Face ◽  
Face Centered ◽  
Average Size

BIOREDUCTION AND CHARACTERIZATION OF SILVER NANOPARTICLES FROM OIL PALM EMPTY FRUIT BUNCH (OPEFB). The synthesis of silver nanoparticles was successfully carried out by extracting oil palm empty fruit bunch. The precursor used was silver nitrate (AgNO3) with a concentration of 9x10-4 M and 5 wt% of the oil palm empty fruit bunch extract. OPEFB acted as a capping agent in the synthesis of silver nanoparticles. The bioreduction method Ag+ to Ag0 produced a silver nanoparticle colloid in brown color. The results of the UV-Vis spectrophotometer showed the silver nanoparticles colloids spectrum at a wavelength of 420 nm with an absorbance value of 0.5. FTIR shows the reduction and shift of absorption peak in the hydroxyl functional group (-OH) at wavenumbers of 3323 cm-1 and the presence of absorption peaks at 560 cm-1. While, XRD pattern showed the specific crystallinity peaks of silver nanoparticles at 2θ: 33.24°; 39.98°; 61.23°; dan 79.13° respectively with the face-centered cubic crystal structure (FCC) and crystallite size of 15 nm. PSA analysis showed two specific peaks with an average size distribution silver nanoparticles of 43.5 nm and a PDI value of 0.4. Analysis of TEM shows the average particle size of 20 nm with a spherical particle shape.

scholarly journals Synthesis and Characterization of Hexadecylamine Capped ZnS, CdS, and HgS Nanoparticles Using Heteroleptic Single Molecular Precursors

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Peter A. Ajibade ◽  
Jejenija Osuntokun
Keyword(s):  
Single Molecule ◽  
Hexagonal Phase ◽  
Average Particle Size ◽  
Cds Nanoparticles ◽  
Cubic Phase ◽  
Average Particle ◽  
Particle Sizes ◽  
Face Centered Cubic ◽  
Molecular Precursors ◽  
Face Centered

Zn(II), Cd(II), and Hg(II) complexes of tetramethyl thiuram disulfides and 1-ethoxylcarbonyl-1-ethylenecarbonyl-2-dithiolate were synthesized and characterized by elemental analysis, FTIR, and1H- and13C-NMR spectroscopy. The complexes were thermolysed in hexadecylamine as single molecule precursors to prepare HDA capped ZnS, CdS, and HgS nanoparticles. The optical and structural properties of the nanoparticles are reported. ZnS nanoparticles existed in the hexagonal phase with particle sizes of 8–15 nm; the CdS nanoparticles in the cubic phase have particle sizes in the range 4–7 nm and the HgS nanoparticles indexed to face-centered cubic phase have an average particle size of 7–12 nm.

Porous NiO-SDC Carbonates Composite Anode for LT-SOFC Applications Produced by Pressureless Sintering

2011 ◽  
Vol 52-54 ◽  
pp. 488-493 ◽  
Author(s):  
Raharjo Jarot ◽  
Andanastuti Muchtar ◽  
Wan Ramli Wan Daud ◽  
Norhamidi Muhamad ◽  
Edy Herianto Majlan
Keyword(s):  
Average Particle Size ◽  
Average Particle ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Weight Percentage ◽  
Composite Anodes ◽  
Optimum Porosity ◽  
Face Centered ◽  
Two Phases ◽  
Cold Pressed

Composite anodes made of NiO and SDC-(Li/Na)2CO3 were investigated in relation to their structure, morphology, and porosity. As a first step, the anode powder was prepared by mixing the NiO with SDC-(Li/Na)2CO3 via solid state reaction in weight percentage of 60 : 40 wt% and in various compositions of carbonates (20 and 30wt%), namely NiO-SDC8020 and NiO-SDC7030, respectively. The powder mixtures were then calcined at 680oC. The resultant powder was fine with surface area of about 13.10-13.70 m2/g and an average particle size of 0.32-0.37µm. The powders consist of two phases i.e. the cubic NiO and face-centered cubic structure SDC-(Li/Na)2CO3 as confirmed with x-ray diffraction. The microstructures were observed under scanning electron microscopy (SEM). The anode pellets were later compacted at different pressures (27, 32 and 37 MPa) and sintered at 600oC. The optimum porosity (20.99-24.78%) was achieved for samples of NiO-SDC8020 and NiO-SDC7030 sintered at 600oC and cold pressed at 32 and 37 MPa.

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

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