The Impregnating Reduction Method for Synthesis of Pt–Ru Nanoparticles and Its Catalytic Performance for Methanol Electro-oxidation

2015 ◽  
Vol 12 (4) ◽  
Author(s):  
Long-long Wang ◽  
Hong-min Mao ◽  
Xiao-jin Zhou ◽  
Qun-jie Xu ◽  
Qiao-xia Li
Keyword(s):  
Reduction Method ◽  
Average Particle Size ◽  
Catalytic Performance ◽  
Average Particle ◽  
X Ray ◽  
Onset Potential ◽  
Ru Nanoparticles ◽  
Oxidation Of Methanol ◽  
Transmission Electron ◽  
Electro Oxidation

Well-dispersed and low Pt content Pt–Ru/C nanoparticles were prepared by a developed impregnating reduction method with sodium citrate as stabilizer. The as-prepared Pt–Ru/C catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. TEM showed that the Pt–Ru particles were quite uniformly distributed on the surface of the carbon with an average particle size of 3.5–4.5 nm. The effect of pH values on methanol electro-oxidation reaction was examined by cyclic voltammetry (CV) and chronoamperometry (CA). Pre-adsorbed CO monolayer stripping was used to evaluate the antipoisoning ability. The results showed that Pt–Ru/C (pH = 8) catalyst had the highest catalytic activity and stability toward the oxidation of methanol. Finally, comparing Pt–Ru/C (Pt–Ru 20 wt.%, Pt/Ru = 1:1) catalysts with Pt/C (Pt 20 wt.%), the onset potential was 200 mV lower and electrochemical active area was much bigger.

A Comparative Study of the Catalytic Performance of Pt-Based Bi and Trimetallic Nanocatalysts Towards Methanol, Ethanol, Ethylene Glycol, and Glycerol Electro-Oxidation

2020 ◽  
Vol 20 (10) ◽  
pp. 6274-6285 ◽  
Author(s):  
Hadla S. Ferreira ◽  
Martin Gocyla ◽  
Hadma S. Ferreira ◽  
Rennan G. O. Araujo ◽  
Caio V. S. Almeida ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Fuel Cells ◽  
Ethylene Glycol ◽  
Inductively Coupled Plasma ◽  
Catalytic Performance ◽  
X Ray ◽  
Onset Potential ◽  
Oxidation Of Methanol ◽  
Catalyst Composition ◽  
Electro Oxidation

Carbon-supported platinum is used as an anode and cathode electrocatalyst in low-temperature fuel cells fueled with low-molecular-weight alcohols in fuel cells. The cost of Pt and its low activity towards the complete oxidation of these fuels are significant barriers to the widespread use of these types of fuel cells. Here, we report on the development of PtRhNi nanocatalysts supported on carbon made using a reduction chemistry method with different atomic rates. The catalytic activity of the developed catalysts towards the electro-oxidation of methanol, ethanol, ethylene glycol, and glycerol in acidic media was studied. The obtained catalysts performances were compared with both commercial Pt/C and binary Pt75Ni25/C catalyst. The nanostructures were characterized, employing inductively coupled plasma optical emission spectrometer, X-ray diffraction, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The binary catalyst presents a mean particle size of around 2 nm. Whereas the ternary catalysts present particles of similar size and with some large alloy and core–shell structures. The alcohol oxidation onset potential and the current density measured after 3600 s of chronoamperometry were used to classify the catalytic activity of the catalysts towards the oxidation of methanol, ethanol, ethylene glycol, and glycerol. The best PtRhNi/C catalyst composition (i.e., Pt43Rh43Ni14/C) presented the highest activity for alcohols oxidation compared with all catalysts studied, indicating the proper tuning composition influence in the catalytic activity. The enhanced activity of Pt43Rh43Ni14/C can be attributed to the synergic effect of trimetallic compounds, Pt, Ni, and Rh.

Biosynthesis and Characterization of Copper Nanoparticles Using a Bioflocculant Extracted from Alcaligenis faecalis HCB2

2019 ◽  
Vol 11 (11) ◽  
pp. 1064-1070 ◽  
Author(s):  
Nkosinathi G. Dlamini ◽  
Albertus K. Basson ◽  
V. S. R. Rajasekhar Pullabhotla
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Copper Nanoparticles ◽  
Average Particle Size ◽  
Thermo Gravimetric Analysis ◽  
Average Particle ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir

Bioflocculant from Alcaligenis faecalis HCB2 was used in the eco-friendly synthesis of the copper nanoparticles. Nanoparticles were characterized using a scanning electron microscope (SEM), transmission electron microscopy (TEM), UV-visible spectroscopy, thermo gravimetric analysis (TGA) and Fourier Transform Infrared Spectroscopy (FT-IR). The transmission electron microscopy images showed close to spherical shapes with an average particle size of ∼53 nm. Energy-dispersive X-ray spectroscopy analysis confirmed the presence of the Cu nanopartilces and also the other elements such as O, C, P, Ca, Cl, Na, K, Mg, and S originated from the bioflocculant. FT-IR results showed the presence of the –OH and –NH2 groups, aliphatic bonds, amide and Cu–O bonds. Powder X-ray diffraction peaks confirmed the presence of (111) and (220) planes of fcc structure at 2 of 33° and 47° respectively with no other impurity peaks.

DIELECTRIC PROPERTIES OF ULTRAFINE Zn-DOPED CaCu3Ti4O12 CERAMIC

2012 ◽  
Vol 02 (01) ◽  
pp. 1250007 ◽  
Author(s):  
LAXMAN SINGH ◽  
U. S. RAI ◽  
K. D. MANDAL ◽  
MADHU YASHPAL
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Single Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Sintered Powder

Ultrafine powder of CaCu2.80Zn0.20Ti4O12 ceramic was prepared using a novel semi-wet method. DTA/TG analysis of dry powder gives pre-information about formation of final product around 800°C. The formation of single phase was confirmed by X-ray diffraction analysis. The average particle size of sintered powder of the ceramic obtained from XRD and Transmission electron microscopy was found 59 nm and 102 nm, respectively. Energy Dispersive X-ray studies confirm the stoichiometry of the synthesized ceramic. Dielectric constant of the ceramic was found to be 2617 at room temperature at 1 kHz.

scholarly journals Biosintesis Nanopartikel Perak Menggunakan Ekstrak Metanol Daun Kemangi (Ocimum Citriodorum)

2017 ◽  
Author(s):  
Yusnita Rifai
Keyword(s):  
Silver Nanoparticles ◽  
Reduction Method ◽  
Average Particle Size ◽  
Mechanical Effect ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Cubic Crystal ◽  
X Ray ◽  
Speed Up ◽  
And Storage

AbstrakNanopartikel perak telah disintesis menggunakan metode reduksi. Dalam penelitian ini, ekstrak metanol daun Kemangi (Ocimum citriodorum) digunakan sebagai agen pereduksi untuk prekursor AgNO3. Sintesis nanopartikel perak dilakukan dengan mencampurkan laru- tan AgNO3 1mM dengan filtrat ekstrak daun kemangi. Hasil karakterisasi UV-Vis menun- jukkan bahwa nilai absorbansi meningkat dengan meningkatnya waktu kontak reaksi. Pun- cak absorbansi spektrum UV-Vis dari sampel biosintesis nanopartikel perak berkisar pada 427-439 nm selama 1 hari dengan pengadukan dan penyimpanan. Ukuran nanopartikel perak ditentukan menggunakan Pengukur Ukuran Partikel (PSA) dengan rata-rata distribusi uku- ran partikel sebesar 57,38 nm. Efek mekanik dalam proses biosintesis nanopartikel perak cenderung mempercepat pembentukan nanopartikel perak. Hasil karakterisasi menggunakan Difraksi Sinar-X (XRD) diketahui kristalit yang terbentuk memiliki intensitas terbesar pada sudut 38° dengan nilai FWHM 0,66310 (ukuran 0,3 nm) dalam sistem kristal kubik.Kata kunci: Biosintesis, Nanopartikel Perak, Ocimum citriodorum, Karakterisasi AbstractSynthesis of silver nanoparticles by using the reduction method with methanol extract basil (Ocimum citriodorum) leaves, which acted as a reducing agent for AgNO3 precursor have been conducted. Synthesis nanoparticles was carried out by mixing the solution of AgNO3 1mM with filtrate extract of Ocimum leaves. The results of characterization showed that absorbance values increased with the increase in reaction time. Peak of UV-Vis absorption spectrum of biosynthesis sample of silver nanoparticles with stirring and storage each at a wavelength 427-439 nm for 1 day. Silver nanoparticles size was determined by using PSA (Particles Size Analyzer) with an average particle size distribution of 57,38 nm. Mechanical effect in biosynthesis process of silver nanoparticles tends to speed up the formation of silver nanoparticles. The result of characterization by using X-Ray Diffraction (XRD) described that the formed crystal had the angle of 38° with the value of FWHM 0,66310 (sixe 0.3 nm) in cubic crystal system.Key word: Biosynthesis, Silver Nanoparticles, Ocimum citriodorum, Characterization.

Studies on conducting nanocomposite with gallium nitride–doped ferrite, part-II

2017 ◽  
Vol 231 (1) ◽  
pp. 53-63
Author(s):  
Rajani Indrakanti ◽  
V Brahmaji Rao ◽  
C Udaya Kiran
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gallium Nitride ◽  
Crystallite Size ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

This article (a sequel to part-I that appeared earlier in the same journal) presents synthesis and characterisation details of conducting PPY-nanocomposite obtained from gallium nitride–doped ferrite and polypyrrole. The GaN-doped ferrite is synthesised by sol–gel method. GaNFe2O3f-PPY composites are prepared by impregnation technique. Using the SciFinder software we could not trace any report in the literature for this synthesised Ga(2x + 2)NFe2(49 − x)O3-PPY nanocomposites. The doped nanoferrite is combined with polypyrrole, an intrinsic conducting polymer, in three proportions by percentage (70%:30%), (90%:10%) and (97%:3%), to obtain two series each of three compositions for the conducting PPY-nanocomposite. The synthesised polymer composites are characterised by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray analysis and Fourier transform infrared spectroscopy. From our studies, it has been observed that the crystallite size of nanocomposites is decreased when compared to crystallite size of GaNFe2O3. The average particle size from histogram is in good agreement with Debye–Scherrer formula calculations. The scanning electron microscopy and transmission electron microscopy micrograms reveal that the particles are varying with the values of X and the percentage of PPY. The shapes observed are Globules,Tetrahedron,Nanorods of short and long lengths. The GaNFe2O3-PPY composites’ spectra revealed the shift in the band in comparison with the PPY spectra. Also, the wavelength is decreased, and vibrational frequency is increased.

SYNTHESIS OF YTTRIA-STABILIZED CUBIC ZIRCONIA NANOCRYSTALS BY ULTRASONIC–MICROWAVE ROUTE

NANO ◽  
2010 ◽  
Vol 05 (05) ◽  
pp. 271-277 ◽  
Author(s):  
JIAN-DONG WANG ◽  
CHONG-XIAO LUO ◽  
JIN-KU LIU ◽  
YI LU ◽  
GUANG-MING LI
Keyword(s):  
Average Particle Size ◽  
Degree Of Crystallinity ◽  
Average Particle ◽  
Stabilized Zirconia ◽  
Uniform Size ◽  
X Ray ◽  
Microwave Assisted ◽  
Transmission Electron ◽  
High Degree ◽  
Microwave Assisted Method

The yttria-stabilized zirconia (YSZ) nanocrystals with uniform size, high purity, and high degree of crystallinity, were prepared by ultrasonic–microwave-assisted method. The structure, optical properties and morphologies of YSZ nanocrystals were characterized by X-ray powder diffraction (XRD), Raman spectroscopy, UV–vis absorption, scanning electron microscope (SEM) and transmission electron microscopy (TEM). The SEM and TEM images of the YSZ nanocrystals indicate that the product is a mono-dispersion structure with an average particle size of about 25 nm.

Investigation on Carbonizing Behaviors of Nanometer-sized Cr2O3 Particles Dispersed on Alumina Particles by Metalorganic Chemical Vapor Deposition in Fluidized Bed

2005 ◽  
Vol 20 (8) ◽  
pp. 2154-2160 ◽  
Author(s):  
Hao-Tung Lin ◽  
Jow-Lay Huang ◽  
Wen-Tse Lo ◽  
Wen-Cheng J. Wei
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Graphite Furnace ◽  
Average Particle Size ◽  
Chemical Vapor ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Alumina Particles

Nanoscaled Cr2O3 powder with an average particle size of 20–40 nm, coated on alumina particles, has been produced by means of chemical vapor deposition (CVD) in a fluidized chamber, using the pyrolysis of Cr(CO)6 precursor. Amorphous and crystalline Cr2O3 particles were obtained when the temperatures of the pyrolysis were 300 and 400 °C, respectively. To prepare nanoscaled Cr3C2 powder from the nanometer-sized Cr2O3, carbonizing behavior of the Cr2O3 particles was investigated. It was found that, when amorphous Cr2O3 powders were carbonized in graphite furnace at 1150 °C for 2 h in vacuum (10−3 Torr), the powder was transformed into Cr3C2, while the crystalline Cr2O3 was transformed into a mixture of Cr7C3 and Cr3C2. The examinations by x-ray diffraction, transmission electron microscopy, and energy dispersive spectroscopy confirmed the transformation of the nano-sized Cr3C2 powders. The results of thermogravimetry and differential thermal analysis indicated that the transformation temperature was ∼1089 °C for amorphous Cr2O3 and ∼1128 °C for crystalline Cr2O3.

The concentration quenching of photoluminescence in Eu3+-doped La2O3

2013 ◽  
Vol 37 (1) ◽  
pp. 47-54 ◽  
Author(s):  
V. Đorđević ◽  
Ž. Antić ◽  
M. G. Nikolić ◽  
M. D. Dramićanin
Keyword(s):  
Room Temperature ◽  
Hexagonal Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Maximum Lifetime ◽  
Transmission Electron ◽  
Lifetime Value ◽  
Kinetics Of

Abstract This work explores the influence of dopant concentration on photoluminescent emission and kinetics of Eu3+-doped (0.2−10 at.%) nanocrystalline lanthanumoxide powders. The X-ray diffraction analysis confirmed that all samples crystallize in La2O3 hexagonal phase with space group P3¯ m1. Transmission electron microscopy showed particles with non-uniform shape and diverse size distribution with an average particle size of (95 ± 5) nm. The room temperature photoluminescence spectra of all samples contain characteristic Eu3+ luminescence lines with the most pronounced red 5D0 →7F2 emission at about 626 nm. The maximum intensity of red emission is observed for the sample containing 5at.% of Eu3+ ions. The emission kinetics was recorded in the temperature range from 10K to 300 K. The maximum lifetime value of 0.98 ms obtained for the sample with 0.5at.% Eu3+ at room temperature increases up to 1.3ms at 10 K.

scholarly journals Synthesis and Characterization of Cu2FeSnSe4 Nanofilms

2021 ◽  
pp. 1873-1878
Author(s):  
Omar Abdulsada Ali ◽  
Sarmed S.M. Al-Awadi
Keyword(s):  
Electron Microscopy ◽  
Average Particle Size ◽  
Average Particle ◽  
Electrochemical Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Photovoltaic Applications ◽  
Tem Transmission Electron Microscopy

Well dispersed Cu2FeSnSe4 (CFTSe) nanofilms were synthesized by hot-injection method. The structural and morphological measurements were characterized using XRD (X-ray diffraction), Raman spectroscopy, SEM (scanning electron microscopy), and TEM (transmission electron microscopy). Chemical composition and optical properties of as-synthesized CFTSe nanoparticles were characterized using EDS (energy dispersive spectroscopy) and UV-Vis spectrophotometry. The average particle size of the nanoparticles was about 7-10 nm. The UV-Vis absorption spectra showed that the synthesized CFTS nanofilms have a band gap (Eg) of about 1.16 eV. Photo-electrochemical characteristics of CFTSe nanoparticles were studied and indicated their potential application in photovoltaic applications.

Preparation of Fe Nanoparticles by Confined Arc Plasma Method

2012 ◽  
Vol 476-478 ◽  
pp. 1206-1209
Author(s):  
Xiao Ju Yao ◽  
Zhi Qiang Wei ◽  
Hua Yang ◽  
Li Gang Liu
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Average Particle ◽  
Arc Plasma ◽  
X Ray ◽  
Plasma Method ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Fe Nanoparticles ◽  
Bcc Structure

In the protecting inert gas, Fe nanoparticles were successfully prepared by confined arc plasma method. The particle size, microstructure and morphology of the particles 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). The experiment results indicate that the samples by this process distributed uniform with spherical chain shapes, the crystal structure is body centered cubic (BCC) structure as same as the bulk materials, the particle size distribution ranging from 20 to 70 nm, with an average particle size about 39 nm obtained by TEM and confirmed by XRD and BET results. The specific surface area is 17.5 m2/g.

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