The Activity and Characterization of Pd/Ce0.5Zr0.5O2 Catalyst for the Reduction of NO

2013 ◽  
Vol 800 ◽  
pp. 93-97
Author(s):  
Xue Tao Wang ◽  
Xu Bin ◽  
Shu Juan Kang ◽  
Cheng Rui Qu
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
Mixed Oxides ◽  
Space Velocity ◽  
X Ray Diffraction ◽  
Intrinsic Structure ◽  
Pd Catalysts ◽  
Reduction Of No ◽  
Xrd Techniques ◽  
Co Precipitation

Pd catalysts and Ce0.5Zr0.5O2 mixed oxides (CZ) was prepared by co-precipitation technique and their physicochemical properties were characterized by specific surface area measurements (BET), scanning electron microscope (SEM), and X-ray diffraction (XRD) techniques. CeO2-ZrO2 solid solutions supported with Pd are investigated as catalysts for reduction of NO. The research presented in this paper is focused on the intrinsic structure of CeO2-ZrO2 solid solution and catalytic behavior of NO over Pd/Ce0.5Zr0.5O2 mixed oxides catalyst. The incorporation of ZrO2 into the CeO2 framework strongly promotes the reduction of Ce4+ in the bulk of the support. The surface area of Ce0.5Zr0.5O2 was 32 m2/g after calcination in air at 1000 °C for 5 h. XRD results revealed the existence of Zr-rich phase in CZ sample. The experimental results show that the best Pd/Ce0.5Zr0.5O2 catalyst yielded 97.75% NO conversion at typical reaction temperatures (280-320 C) and the high gas hourly space velocity of 15,000 h1. The effect of the calcination temperature was also investigated, and the optimal calcination temperature was 400-500 C.

Microstructure Characterization of Metal Mixed Oxides

MRS Advances ◽  
2017 ◽  
Vol 2 (64) ◽  
pp. 4025-4030 ◽  
Author(s):  
T. Kryshtab ◽  
H. A. Calderon ◽  
A. Kryvko
Keyword(s):  
Mixed Oxides ◽  
Profile Analysis ◽  
Atomic Resolution ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Reconstruction Procedure ◽  
Transmission Electron ◽  
Xrd Patterns ◽  
Co Precipitation

ABSTRACTThe microstructure of Ni-Mg-Al mixed oxides obtained by thermal decomposition of hydrotalcite-like compounds synthesized by a co-precipitation method has been studied by using X-ray diffraction (XRD) and atomic resolution transmission electron microscopy (TEM). XRD patterns revealed the formation of NixMg1-xO (x=0÷1), α-Al2O3 and traces of MgAl2O4 and NiAl2O4 phases. The peaks profile analysis indicated a small grain size, microdeformations and partial overlapping of peaks due to phases with different, but similar interplanar spacings. The microdeformations point out the presence of dislocations and the peaks shift associated with the presence of excess vacancies. The use of atomic resolution TEM made it possible to identify the phases, directly observe dislocations and demonstrate the vacancies excess. Atomic resolution TEM is achieved by applying an Exit Wave Reconstruction procedure with 40 low dose images taken at different defocus. The current results suggest that vacancies of metals are predominant in MgO (NiO) crystals and that vacancies of Oxygen are predominant in Al2O3 crystals.

scholarly journals Copper-Containing Mixed Metal Oxides (Al, Fe, Mn) for Application in Three-Way Catalysis

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1344
Author(s):  
Tim Van Everbroeck ◽  
Radu-George Ciocarlan ◽  
Wouter Van Hoey ◽  
Myrjam Mertens ◽  
Pegie Cool
Keyword(s):  
Catalytic Activity ◽  
Spinel Structure ◽  
Mixed Oxides ◽  
High Catalytic Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Application ◽  
Mixed Spinel ◽  
Co Precipitation ◽  
Three Way Catalysis

Mixed oxides were synthesized by co-precipitation of a Cu source in combination with Al, Fe or Mn corresponding salts as precursors. The materials were calcined at 600 and 1000 °C in order to crystallize the phases and to mimic the reaction conditions of the catalytic application. At 600 °C a mixed spinel structure was only formed for the combination of Cu and Mn, while at 1000 °C all the materials showed mixed spinel formation. The catalysts were applied in three-way catalysis using a reactor with a gas mixture containing CO, NO and O2. All the materials calcined at 600 °C displayed the remarkable ability to oxidize CO with O2 but also to reduce NO with CO, while the pure oxides such as CuO and MnO2 were not able to. The high catalytic activity at 600 °C was attributed to small supported CuO particles present and imperfections in the spinel structure. Calcination at 1000 °C crystallized the structure further which led to a dramatic loss in catalytic activity, although CuAl2O4 and CuFe2O4 still converted some NO. The materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, H2-Temperatrue Programmed Reduction (H2-TPR), N2-sorption and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX).

The Influence of Calcination Temperature on Quantitative Phase of Hematite from Iron Stone Tanah Laut

2015 ◽  
Vol 1112 ◽  
pp. 489-492
Author(s):  
Ali Mufid ◽  
M. Zainuri
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Thermo Gravimetric Analysis ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Particle Size Analyzer ◽  
Co Precipitation

This research aims to form particles of hematite (α-Fe2O3) with a basis of mineral iron ore Fe3O4 from Tanah Laut. Magnetite Fe3O4 was synthesized using co-precipitation method. Further characterization using X-ray fluorescence (XRF) to obtain the percentage of the elements, obtained an iron content of 98.51%. Then characterized using thermo-gravimetric analysis and differential scanning calorimetry (TGA-DSC) to determine the calcination temperature, that at a temperature of 445 °C mass decreased by 0.369% due to increase in temperature. Further Characterization of X-ray diffraction (XRD) to determine the phases formed at the calcination temperature variation of 400 °C, 445 °C, 500 °C and 600 °C with a holding time of 5 hours to form a single phase α-Fe2O3 hematite. Testing with a particle size analyzer (PSA) to determine the particle size distribution, where test results indicate that the α-Fe2O3 phase of each having a particle size of 269.7 nm, 332.2 nm, 357.9 nm, 412.2 nm. The best quantity is shown at a temperature of 500 °C to form the hematite phase. This result is used as the calcination procedure to obtain a source of Fe ions in the manufacture of Lithium Ferro Phosphate.

Transformation of Methane into Synthesis Gas Using the Redox Property of Pr-Zr Mixed Oxides: Effect of Calcination Temperature

2013 ◽  
Vol 724-725 ◽  
pp. 1187-1191
Author(s):  
Yong Gang Wei ◽  
Yun Peng Du ◽  
Kong Zhai Li ◽  
Xing Zhu ◽  
Hua Wang
Keyword(s):  
Calcination Temperature ◽  
Synthesis Gas ◽  
Mixed Oxides ◽  
Structural Evolution ◽  
Temperature Stability ◽  
Phase Segregation ◽  
Oxygen Carriers ◽  
High Temperature Stability ◽  
Calcination Temperatures ◽  
Co Precipitation

Pr-Zr mixed oxides prepared by co-precipitation were used as oxygen carriers for converting methane into synthesis gas through gas-solid reactions. The structural evolution and reducibility of Pr-Zr oxygen carriers with calcination temperatures from 600 to 1200°C were investigated by XRD and TPR techniques and correlated to their activity for methane selective oxidation. The Pr-Zr mixed oxides calcined at 600-800°C show outstanding thermostability, and higher calcination temperatures result in phase segregation. Pr0.7Zr0.3O2-δ possesses high temperature stability(<900 °C) and the best appropriate calcination temperature is 800°C for methane gas-solid reaction.

Influence of Preparation Parameters on the New NSR Catalyst Support Material

2011 ◽  
Vol 412 ◽  
pp. 361-364
Author(s):  
Wei Jun Zhang ◽  
Yuan Feng Huang ◽  
Li Shen ◽  
Jun Liu ◽  
Xiao Qing Luo ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Calcination Temperature ◽  
Specific Surface Area ◽  
Catalyst Support ◽  
Atomic Ratio ◽  
High Specific Surface Area ◽  
Support Material ◽  
Co Precipitation

A series of Ba-Al-O/NSR supports were prepared by co-precipitation in this work. The effect of Al/Ba atomic ratio and calcination temperature on the structure and texture of the supports was investigated carefully. The XRD spectra show that Ba is mainly exist in the form of BaAl2O4, and Al exists in Al2O3. The results of SBET indicate that the supports possess relative high specific surface area (70~150 m2/g). The effect of different parameters on the process of supports synthesized was investigated carefully. The results show that the structure and specific surface area of support is significantly depended on calcination temperature.

Co-Precipitation Synthesis of BiFeO3 Powders

2010 ◽  
Vol 105-106 ◽  
pp. 286-288 ◽  
Author(s):  
Hai Yang Bo ◽  
Guo Qiang Tan ◽  
Hong Yan Miao ◽  
Ao Xia
Keyword(s):  
Calcination Temperature ◽  
Bismuth Ferrite ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Infrared Spectrophotometer ◽  
Lower Temperature ◽  
Co Precipitation

Bismuth ferrite powders were synthesized by a simple citric acid complexing co-precipitation method at much lower temperature of 600°C. The work studies the calcination temperature and molar ratio of Fe and Bi on the structure and morphology. The as-prepared BiFeO3 powder was characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscope and Fourier transform infrared spectrophotometer. The result shows that the phase pure BiFeO3 powders with cubic morphology were prepared as the calcination temperature was 600°C and molar ratio of Fe and Bi was 1:1. The nanoparticles was uniform with the size of about 200nm.

scholarly journals The Fabrication of Natural Zeolite Via Co-Precipitation Method as Cu, Pb and Zn Metal Absorbent

2020 ◽  
Vol 57 (3) ◽  
pp. 40-47
Author(s):  
M. Sirait ◽  
K.Sari Dewi Saragih ◽  
S. Gea ◽  
Keyword(s):  
Heavy Metal ◽  
Surface Area ◽  
Natural Zeolite ◽  
Total Surface Area ◽  
Precipitation Method ◽  
Natural Material ◽  
X Ray Diffraction ◽  
Test Analysis ◽  
Living Things ◽  
Co Precipitation

AbstractHeavy metal waste is very dangerous, which can change the condition of water into a solid substance that can be suspended in water and can reduce the cleanliness level of water consumed by living things. To date, heavy metals can be managed through several processes, namely physics, biology or chemistry. One of the ways to overcome heavy metal pollution is to use natural zeolite applying a co-precipitation method, as it is known that zeolite is a powerful natural material to be used for certain purposes. In order to justify the research results, several analyses have been performed, such as X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Surface Area Analyser (SAA), and Atomic Adsorption Spectrophotometric (AAS). From the XRD results, it has been found out that the size of each zeolite with variations in size of 150 mesh, 200 mesh, and 250 mesh is 29.274 nm, 38.665 nm and 43.863 nm, respectively. Moreover, the SEM-EDX has shown that the zeolite under consideration is a type of Na-Zeolite and that the co-precipitation method successfully removes impurity elements, namely, Fe, Ti, and Cl. The results of SAA testing have indicated that the total surface area for each variation of zeolite sizes is 63.23 m2/g, 45.14 m2/g and 59.76 m2/g. The results of the AAS test analysis have demonstrated that the optimal absorption of metal content is observed in a size of 150 mesh zeolite with adsorption power of 99.6 % for Pb metal, 98 % for Cu metal, and 96 % Zn metal.

scholarly journals W-Sn Mixed Oxides and ZnO to Detect NOx and Ozone in Atmosphere

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 836
Author(s):  
Ambra Fioravanti ◽  
Sara Morandi ◽  
Alessia Amodio ◽  
Mauro Mazzocchi ◽  
Michele Sacerdoti ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mixed Oxides ◽  
Gas Sensing ◽  
Molar Fraction ◽  
Functional Materials ◽  
X Ray Diffraction ◽  
X Ray

Thick films of zinc oxide (ZnO) in form of nanospheres or hexagonal prisms and of tungsten-tin (W-Sn) mixed oxides at nominal Sn molar fraction (0.1, 0.3 and 0.5) were prepared. The functional materials were synthesized and characterized by SEM and TEM, X-ray diffraction, specific surface area measurements, UV-Vis-NIR and IR spectroscopies. The gas sensing measurements highlighted that ZnO is more performant in form of nanoprisms, while W-Sn sensors offer a better response towards NOx and ozone with respect to pure WO3.

ADSORPTION OF CYCLOHEXANE AND BENZENE ON MIXED HYDROXIDES AND OXIDES OF MAGNESIUM AND ALUMINIUM

1966 ◽  
Vol 44 (8) ◽  
pp. 877-884 ◽  
Author(s):  
R. I. Razouk ◽  
Sh. Nashed ◽  
F. N. Antonious
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Surface Area ◽  
Structural Changes ◽  
Mixed Oxides ◽  
X Ray Diffraction ◽  
Oxide Systems ◽  
X Ray ◽  
Characteristic Lines

Seven mixed hydroxides of magnesium and aluminium were prepared, and phase and structural changes accompanying their dehydration were investigated by differential thermal analysis, thermogravimetric analysis, and X-ray diffraction techniques. The differential thermal analysis curves possess 2 peaks corresponding to those of parent hydroxides together with a new peak, and the thermogravimetric analysis curves show slight inflections. X-ray diffraction patterns of the mixed hydroxides possess the characteristic lines of the parent hydroxides together with three to five new intense lines which might indicate the formation of a double hydroxide. When the mixed hydroxides are progressively heated they give rise to products possessing patterns which first become diffuse and ultimately pass mainly into the spinel pattern.Adsorption isotherms of cyclohexane and benzene were measured on the mixed hydroxides and their dehydration products. Specific surface areas calculated by the application of the Brunauer, Emmett, Teller (B.E.T.) equation are in general in good agreement for the two adsorbates. The surface area increases with rise of dehydration temperature to a maximum at 500–600 °C and then decreases with further rise in temperature. This behavior is common to crystalline oxide systems and may be ascribed to the intermingling of decomposition, re-crystallization, and sintering processes. Variations in the molecular ratio of the mixed oxides (as much as 20-fold), and in the method of preparation, do not much alter the surface area.

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