Structural Characterization and CO Oxidation Activity of Nanostructured LaMnO3 Catalysts

2002 ◽  
Vol 55 (12) ◽  
pp. 757 ◽  
Author(s):  
Min Chen ◽  
Huai-Qing Huang ◽  
Xiao-Ming Zheng ◽  
Michael A. Morris
Keyword(s):  
Co Oxidation ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Total Oxidation ◽  
Oxidation Activity ◽  
Preparation Methods ◽  
Synthesis Conditions ◽  
Nanostructured Particles ◽  
Transmission Electron ◽  
Perovskite Type

Perovskite-type LaMnO3 catalysts were prepared by three different methods and tested for CO oxidation. The structural character of the catalysts was investigated by using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). All three different preparation methods resulted in nanostructured particles forming in the LaMnO3 catalysts. The crystallite size was in the range of 20 to 80 nm depending on the synthesis conditions. It was possible to synthesize the smallest particle size and a pure phase of perovskite-type LaMnO3 oxide by using a sol–gel method. The results also indicated that the CO total oxidation activity was related to the size of LaMnO3 particle and the structure formed.

scholarly journals Evaluation of NO Oxidation Properties over a Mn-Ce/γ-Al2O3Catalyst

2016 ◽  
Vol 2016 ◽  
pp. 1-5
Author(s):  
Pan Wang ◽  
Peng Luo ◽  
Junchen Yin ◽  
Lili Lei
Keyword(s):  
Electron Microscope ◽  
Sol Gel ◽  
Diesel Oxidation Catalyst ◽  
No Oxidation ◽  
Oxidation Catalyst ◽  
X Ray Diffraction ◽  
Oxidation Activity ◽  
Transmission Electron ◽  
Diesel Oxidation ◽  
Oxidation Properties

With the purpose of studying the effect of diesel oxidation catalyst (DOC) on the NO oxidation activity, a series ofxMn10Ce/γ-Al2O3(x= 4, 6, 8, and 10) catalysts were synthesized by acid-aided sol-gel method. The physicochemical properties of the catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Transmission Electron Microscope (TEM). Result showed that the crystalline size of MnOxand CeO2ranges from 5 nm to 30 nm and manganese existed mainly in the catalysts in the form of manganese dioxide. Moreover, NO oxidation experiments were carried out to evaluate the activity of the catalysts; according to the results, 6Mn10Ce/γ-Al2O3catalyst showed the supreme NO oxidation activity with a NO to NO2conversion rate of 83.5% at 300°C. Compared to 500 ppm NO inlet concentration, the NO conversion was higher than that of 750 and 1000 ppm NO over 6Mn10Ce/γ-Al2O3catalyst in the temperature range of 150–300°C.

scholarly journals Facile Sol-gel Synthesis of Porous Silicas Using Poly(propylene)imine Dendrimers as Templates

2000 ◽  
Vol 15 (8) ◽  
pp. 1842-1848 ◽  
Author(s):  
Gustavo Larsen ◽  
Edgar Lotero ◽  
Manuel Marquez
Keyword(s):  
Single Molecule ◽  
Sol Gel ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Template Removal ◽  
Synthesis Conditions ◽  
Transmission Electron ◽  
Argon Adsorption ◽  
Poly Propylene ◽  
Sol Gel Synthesis

Commercially available poly(propylene)imine (DAB-Am-32 and DAB-Am-64) dendrimers were used as single-molecule templates to tailor the porosity of silicas via a nonacidic sol-gel method. X-ray diffraction on both the as-prepared (oven-dried at 373 K) and the calcined (833 K) materials revealed that modest contraction took place on template removal and that the cavities created did not achieve three-dimensional ordering under the current synthesis conditions. Transmission electron microscopy of “Pt-stained” samples supported this picture. A modified Horvath–Kawazoe analysis of the argon adsorption isotherms indicated that DAB-Am-64 is a much more effective template than DAB-Am-32. Pyrolysis and oxidation protocols for template removal are also presented.

scholarly journals Thermal CO Oxidation and Photocatalytic CO2 Reduction over Bare and M-Al2O3 (M = Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) Cotton-Like Nanosheets

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1278
Author(s):  
Heejung Yoon ◽  
Juhyun Yang ◽  
Sojeong Park ◽  
Youngku Sohn
Keyword(s):  
Electron Microscopy ◽  
Transition Metals ◽  
Co Oxidation ◽  
Photoelectron Spectroscopy ◽  
Co2 Reduction ◽  
Data Sets ◽  
X Ray Diffraction ◽  
Oxidation Activity ◽  
X Ray ◽  
Transmission Electron

Aluminum oxide (Al2O3) has abundantly been used as a catalyst, and its catalytic activity has been tailored by loading transition metals. Herein, γ-Al2O3 nanosheets were prepared by the solvothermal method, and transition metals (M = Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) were loaded onto the nanosheets. Big data sets of thermal CO oxidation and photocatalytic CO2 reduction activities were fully examined for the transition metal-loaded Al2O3 nanosheets. Their physicochemical properties were examined by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction crystallography, and X-ray photoelectron spectroscopy. It was found that Rh, Pd, Ir, and Pt-loading showed a great enhancement in CO oxidation activity while other metals negated the activity of bare Al2O3 nanosheets. Rh-Al2O3 showed the lowest CO oxidation onset temperature of 172 °C, 201 °C lower than that of bare γ-Al2O3. CO2 reduction experiments were also performed to show that CO, CH3OH, and CH4 were common products. Ag-Al2O3 nanosheets showed the highest performances with yields of 237.3 ppm for CO, 36.3 ppm for CH3OH, and 30.9 ppm for CH4, 2.2×, 1.2×, and 1.6× enhancements, respectively, compared with those for bare Al2O3. Hydrogen production was found to be maximized to 20.7 ppm during CO2 reduction for Rh-loaded Al2O3. The present unique pre-screening test results provided very useful information for the selection of transition metals on Al2O3-based energy and environmental catalysts.

Evaluation of Novel Nanophase Ce0.8Sr0.2Fe0.9Ir0.1O3-δ as Cathode Material for Low Temperature SOFC

2016 ◽  
Vol 44 ◽  
pp. 35-50 ◽  
Author(s):  
Chima Benjamin Njoku ◽  
Patrick Gathura Ndungu
Keyword(s):  
Electron Microscopy ◽  
Solid Oxide Fuel Cells ◽  
Cathode Material ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Low Temperature Sofc ◽  
Gel Technique ◽  
Perovskite Type ◽  
A Current

In this study, Ce0.8Sr0.2Fe0.9Ir0.1O3-δ (CSFI) perovskite type material was prepared by sol-gel technique, characterised, and then tested as a cathode material for solid oxide fuel cells operating between 300 – 500 °C. The materials were studied using X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The morphology was examined using scanning electron microscopy and high resolution transmission electron microscopy. Samples showed changes in the overall structure and defect chemistry with an increase in calcination temperature. When tested as cathode materials, the material calcined at 1000 °C had the greatest performance at a test temperature of 500 °C, with a current density of 774.47 mA/cm2, a power density of 483.07 mW/cm2 and an area specific resistance (ASR) of 0.342 Ω/cm2.

Preparation and Characterization of Perovskite-Type Oxide Catalysts for Combustion of Methane

2012 ◽  
Vol 427 ◽  
pp. 77-81
Author(s):  
Gang Xue ◽  
Xue Fang Zhang ◽  
Sai Fei Wang ◽  
Chao Yue Zhao
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Sol Gel ◽  
Perfect Crystal ◽  
Activity Measurement ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Microscopy Techniques ◽  
Perovskite Type

A series of rare earth perovskite-type oxides La09Sr0.1Co0.9Mn0.1O3La08Sr0.2Co0.8Mn0.2O3and La05Sr0.5Co0.5Mn0.5O3were prepared along the sol-gel method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), transmission electron microscopy techniques (TEM) and catalytic activity measurement for combustion of CH4. The results indicated that a perfect crystal structure of perovskite was formed and La3+and Co3+ions were partly replaced by Sr2+and Mn3+ions, respectively, and perovskite-type oxides were composed of nanocrystals with particle size of 20~50nm. The catalytic activity for the combustion of CH4 was evaluated and La05Sr0.5Co0.5Mn0.5O3exhibited best performance with the temperature of 50% and 90% conversion efficiency of 723K and 833K.

Preparation of Gold Nanoparticles Supported on Montmorillonite and its Catalytic Activity for CO Oxidation

2014 ◽  
Vol 955-959 ◽  
pp. 51-55
Author(s):  
Ting Ting Hu ◽  
Lin Hua Zhu
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Oxidation Reaction ◽  
Fluorescence Analysis ◽  
X Ray Diffraction ◽  
Oxidation Activity ◽  
X Ray ◽  
Transmission Electron ◽  
Gold Precursor

Gold catalysts supported on Na-MMT and Al-PILM noted as Au/Na-MMT and Au/Al-PILM respectively were prepared using Au(en)2Cl3 as precursor, and the catalytic oxidation activity for CO oxidation was investigated. The influence of different carriers on the conversion of CO was discussed. The phase of catalysts, the actual gold loading and the morphology of gold nanoparticles were characterized by X-ray diffraction(XRD), X-ray fluorescence analysis(XRF) and Transmission electron microscopy(TEM). The results showed that Au/Al-PILM exhibited higher catalytic activity for the oxidation reaction of CO, and 100% conversion of CO was achieved at reaction temperature of 250°C when gold precursor was loaded on the Al-PILM carrier at 60°Cand calcined it at 450°C for 1h.

Preparation and Characterization of La0.9Sr0.1Co0.5Mn0.5O3 Composite Catalytic Materials for Conversion of Exhaust Gas from Natural Gas Automobiles

2010 ◽  
Vol 178 ◽  
pp. 202-209
Author(s):  
Xue Fang Zhang ◽  
Gang Xue ◽  
Jin Sheng Liang ◽  
Lei Zhang
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Perfect Crystal ◽  
Exhaust Gas ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Perovskite Crystal ◽  
Perfect Crystal Structure ◽  
Perovskite Type

A series of rare earth perovskite-type oxides La0.9Sr0.1CoO3, La0.9Sr0.1MnO3 and La0.9Sr0.1Co0.5Mn0.5O3 were prepared by sol-gel method and characterized by X-ray diffraction (XRD), specific surface analysis (BET), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) techniques. The results showed that for La0.9Sr0.1Co0.5Mn0.5O3 sample, Sr2+ and Mn3+ ions partly replaced La3+ and Co3+ ions and entered perovskite crystal lattice, and finally a perfect crystal structure of perovskite was formed. Moreover, these powders presented sphericity granules with particle size of about 20nm and satisfactory pore structure. With the doping of Sr2+ ions in a certain range, the coexisting system of Mn3+- Mn4+ and Co3+- Co4+ as well as the concentration of oxygen vacancies were increased, thus leading to the higher catalytic activity of the prepared catalysts.

scholarly journals The Influence Of NO/O2 On The NOx Storage Properties Over A Pt-Ba-Ce/γ-Al2O3 Catalyst

2019 ◽  
Vol 17 (1) ◽  
pp. 1459-1465
Author(s):  
Xuedong Feng ◽  
Jing Yi ◽  
Peng Luo
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
No Oxidation ◽  
Test Results ◽  
X Ray Diffraction ◽  
Storage Performance ◽  
Transmission Electron ◽  
Temperature Programmed ◽  
Physical And Chemical ◽  
Al2o3 Catalyst

AbstractWith the purpose of studying the influence of NO/O2 on the NOx storage activity, a Pt-Ba-Ce/γ-Al2O3 catalyst was synthesized by an acid-aided sol-gel method. The physical and chemical properties of the catalyst were characterized by X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) methods. The results showed that the composition of the catalyst was well-crystallized and the crystalline size of CeO2 (111) was about 5.7 nm. The mechanism of NO and NO2 storage and NOx temperature programmed desorption (NO-TPD) experiments were investigated to evaluate the NOx storage capacity of the catalyst. Pt-Ba-Ce/γ-Al2O3 catalyst presented the supreme NOx storage performance at 350℃, and the maximum value reached to 668.8 μmol / gcat. Compared with O2-free condition, NO oxidation to NO2 by O2 had a beneficial effect on the storage performance of NOx. NO-TPD test results showed that the NOx species stored on the catalyst surface still kept relatively stable even below 350℃.

scholarly journals V2O3/C composite fabricated by carboxylic acid-assisted sol–gel synthesis as anode material for lithium-ion batteries

2021 ◽  
Author(s):  
G. S. Zakharova ◽  
E. Thauer ◽  
A. N. Enyashin ◽  
L. F. Deeg ◽  
Q. Zhu ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Lithium Ion Batteries ◽  
Sol Gel ◽  
Carbon Sources ◽  
Lithium Ion ◽  
X Ray Diffraction ◽  
Electron Microscopies ◽  
Transmission Electron ◽  
Battery Electrode ◽  
Sol Gel Synthesis

AbstractThe potential battery electrode material V2O3/C has been prepared using a sol–gel thermolysis technique, employing vanadyl hydroxide as precursor and different organic acids as both chelating agents and carbon sources. Composition and morphology of resultant materials were characterized by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopies, physical sorption, and elemental analysis. Stability and electronic properties of model composites with chemically and physically integrated carbon were studied by means of quantum-chemical calculations. All fabricated composites are hierarchically structured and consist of carbon-covered microparticles assembled of polyhedral V2O3 nanograins with intrusions of amorphous carbon at the grain boundaries. Such V2O3/C phase separation is thermodynamically favored while formation of vanadium (oxy)carbides or heavily doped V2O3 is highly unlikely. When used as anode for lithium-ion batteries, the nanocomposite V2O3/C fabricated with citric acid exhibits superior electrochemical performance with an excellent cycle stability and a specific charge capacity of 335 mAh g−1 in cycle 95 at 100 mA g−1. We also find that the used carbon source has only minor effects on the materials’ electrochemical performance.

Effect of Calcinations on Characterizations of Fabricated Nano Manganese Ferrite

2013 ◽  
Vol 634-638 ◽  
pp. 2150-2154 ◽  
Author(s):  
Rita Sundari ◽  
Tang Ing Hua ◽  
M. Rusli Yosfiah
Keyword(s):  
Sol Gel ◽  
Volatile Components ◽  
Manganese Ferrite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Reflectance Analysis ◽  
Transmission Electron Microscope Analysis ◽  
Electron Microscope Analysis ◽  
Nano Size

A citric acid anionic surfactant has been applied for nano manganese ferrite (MnFeO3) fabrication using sol gel method. The calcinations have been varied for 300, 600 and 800oC. The UVDR (UV-Vis Diffused Reflectance) analysis shows a high absorptive band gap after 400 nm for the 600oC calcinated MnFeO3. The DTA (Differential Thermal Analysis) profiles exhibit remarkably trapped volatile matters (H2O, CO2, and NO2) in the fabricated MnFeO3 under sol gel heat treatment at 100oC and the peaks disappeared as the calcination increased to 600oC. As the temperature elevated from 100 to 300oC, the absorption peaks of volatile components are disappeared as demonstrated clearly by the FTIR (Fourier Transform Infrared) spectra of the fabricated material, which 3393 cm-1 corresponded to OH group, 1624 cm-1 to CO group, and 1384 cm-1 to NO group. The XRD (X-Ray Diffraction) spectra show clearly the alteration process from amorphous to crystalline structure as the calcinations increased from 300 to 600oC. In addition, the TEM (Transmission Electron Microscope) analysis exhibits parts of the fabricated MnFeO3 found in cubic nano size of 15-40 nm under interested calcinations and the result is in agreement with that obtained by XRD investigation.

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