Synthesis of nanostructured perovskite powders via simple carbonate co-precipitation

2013 ◽  
Vol 67 (5) ◽  
Author(s):  
Cinzia Cristiani ◽  
Giovanni Dotelli ◽  
Mario Mariani ◽  
Renato Pelosato ◽  
Luca Zampori
Keyword(s):  
High Temperature ◽  
Crystallite Size ◽  
Cost Effective ◽  
Perovskite Oxides ◽  
X Ray ◽  
Surface Areas ◽  
Precipitation Synthesis ◽  
Lanthanum Manganese Oxide ◽  
Co Precipitation ◽  
Perovskite Type

AbstractA very simple, cost-effective, chloride- and alkali-free, carbonate co-precipitation synthesis in aqueous medium was applied in the preparation of perovskite-type lanthanum manganese oxide-based powders, i.e. La0.70Sr0.30MnO3−δ (LSM) and La0.75Sr0.25Cr0.5Mn0.5O3−δ (LSCrM). The precursors so obtained yielded nano-structured perovskite oxides when treated at 900°C and 800°C, respectively. The measured BET surface areas were in the low-end range for high temperature oxides (4 m2 g−1 and 10 m2 g−1) but the X-ray crystallite size was as low as 50 nm for LSCrM and 90 nm for LSM.

scholarly journals Einkristall-Röntgenstrukturanalyse von Ba3CeIVRu2IVO9, Ba3LnIII,Ru2IV/VO9 (Ln = Sm, Dy, Er) und Ba3Ti2,4Ru0,6O9 / Single Crystal X-Ray Analysis of Ba3CeIVRu2IVO9, Ba3LnIII,Ru2IV/VO9 (Ln = Sm, Dy, Er) and Ba3Ti2,4Ru0,6O9

1996 ◽  
Vol 51 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Hk. Müller-Buschbaum ◽  
B. Mertens
Keyword(s):  
High Temperature ◽  
Lattice Energy ◽  
Solid State Reactions ◽  
Hexagonal Symmetry ◽  
X Ray ◽  
Valence States ◽  
Group D ◽  
Symmetry Space ◽  
Perovskite Type ◽  
Symmetry Space Group

Single crystals of (I) Ba3CeRu2O9, (II) Ba3SmRu2O9, (III) Ba3DyRu2O9, (IV) Ba3ErRu2O9 and (V) Ba3Ti2 4Ru0,6O9 have been prepared by high temperature solid state reactions. The compounds were examined by X-ray techniques. They crystallize with hexagonal symmetry, space group D46h-P63/mmc with (I): a = 5.8738(7), c = 14.585(4); (II): a = 5.9137(5), c = 14.651(2); (III): a = 5.8805(5), c = 14.506(1); (IV): a = 5.8737(9), c = 14.470(3); (V): a = 5.7265(6), c = 14.006(2) Å, Z = 2. The crystal structures belong to the 6 L-perovskite type. Calculations of the Coulomb terms of the lattice energy led to the valence states (I): CeIV/RuIV and (II)-(IV): LnIII,/RuIV/V. (V) shows a partial statistic distribution of TiIV and RuIV.

Study of Preparation, Characterization and Temperature-Programmed Reduction of NiO-ZnO Binary Materials

2013 ◽  
Vol 664 ◽  
pp. 515-520
Author(s):  
Chih Wei Tang ◽  
Jiunn Jer Hwang ◽  
Shie Hsiung Lin ◽  
Chin Chun Chung
Keyword(s):  
Weight Percent ◽  
Precipitation Method ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Temperature Programmed ◽  
Co Precipitation ◽  
Adsorption Desorption

The NiO-ZnO binary materials had been prepared by co-precipitation method. The weight percent of nickel of NiO-ZnO materials were 5, 10 and 20; they were pretreated under air at temperature of 300, 500 and 700°C, respectively. The characterization of NiO-ZnO materials were the thermal gravity analysis(TGA), X-ray diffraction(XRD), N2 adsorption-desorption at 77K, scaning electron microscope(SEM) and temperature-programmed reduction(TPR). The results revealed that surface areas of NiO-ZnO materials order from large to small were 20NiZn(OH)x(66 m2·g-1) > 10NiZn(OH)x(34 m2·g-1) > 5NiZn(OH)x(9 m2·g-1) after being calcined at the temperature of 500°C. Further, NiO-ZnO materials had two main reductive peaks at 390-415°C and 560-657°C, respectively. In all NiO-ZnO materials, 20NiZn(OH)x-C500 material had the highest surface area and the best interaction between NiO and ZnO.

scholarly journals Lanthanum based high surface area perovskite-type oxide and application in CO and propane combustion

2018 ◽  
Vol 34 (1) ◽  
pp. 31
Author(s):  
Paulo Roberto Nagipe Da Silva ◽  
Ana Brígida Soares
Keyword(s):  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Perovskite Phase ◽  
High Surface ◽  
High Surface Area ◽  
Propane Combustion ◽  
Total Oxidation ◽  
X Ray ◽  
Co Precipitation ◽  
Perovskite Type

The perovskite-type oxides using transition metals present a promising potential as catalysts in total oxidation reaction. The present work investigates the effect of synthesis by oxidant co-precipitation on the catalytic activity of perovskite-type oxides LaBO3 (B= Co, Ni, Mn) in total oxidation of propane and CO. The perovskite-type oxides were characterized by means of X-ray diffraction, nitrogen adsorption (BET method), thermo gravimetric and differential thermal analysis (ATG-DTA) and X-ray photoelectron spectroscopy (XPS). Through a method involving the oxidant co-precipitation it’s possible to obtain catalysts with different BET surface areas, of 33-44 m2/g, according the salts of metal used. The characterization results proved that catalysts have a perovskite phase as well as lanthanum oxide, except LaMnO3, that presents a cationic vacancies and generation for known oxygen excess. The results of catalytic test showed that all oxides have a specific catalytic activity for total oxidation of CO and propane even though the temperatures for total conversion change for each transition metal and substance to be oxidized.

scholarly journals Resolving the effects of 2-D versus 3-D grain measurements on apatite (U–Th) ∕ He age data and reproducibility

Geochronology ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 17-41 ◽  
Author(s):  
Emily H. G. Cooperdock ◽  
Richard A. Ketcham ◽  
Daniel F. Stockli
Keyword(s):  
Surface Area ◽  
Ct Scanning ◽  
Cost Effective ◽  
X Ray ◽  
Surface Areas ◽  
Two Samples ◽  
Sphere Radius ◽  
Ct Data ◽  
Small Aliquot ◽  
Sample Age

Abstract. (U–Th) ∕ He thermochronometry relies on the accurate and precise quantification of individual grain volume and surface area, which are used to calculate mass, alpha ejection (FT) correction, equivalent sphere radius (ESR), and ultimately isotope concentrations and age. The vast majority of studies use 2-D or 3-D microscope dimension measurements and an idealized grain shape to calculate these parameters, and a long-standing question is how much uncertainty these assumptions contribute to observed intra-sample age dispersion and accuracy. Here we compare the results for volume, surface area, grain mass, ESR, and FT correction derived from 2-D microscope and 3-D X-ray computed tomography (CT) length and width data for > 100 apatite grains. We analyzed apatite grains from two samples that exhibited a variety of crystal habits, some with inclusions. We also present 83 new apatite (U–Th) ∕ He ages to assess the influence of 2-D versus 3-D FT correction on sample age precision and effective uranium (eU). The data illustrate that the 2-D approach systematically overestimates grain volumes and surface areas by 20 %–25 %, impacting the estimates for mass, eU, and ESR – important parameters with implications for interpreting age scatter and inverse modeling. FT factors calculated from 2-D and 3-D measurements differ by ∼2 %. This variation, however, has effectively no impact on reducing intra-sample age reproducibility, even on small aliquot samples (e.g., four grains). We also present a grain-mounting procedure for X-ray CT scanning that can allow hundreds of grains to be scanned in a single session and new software capabilities for 3-D FT and FT-based ESR calculations that are robust for relatively low-resolution CT data, which together enable efficient and cost-effective CT-based characterization.

Synthesis of Fe-Mn-Ce SCR Catalyst by Precipitation Method Using Different Precipitating Agents

2011 ◽  
Vol 347-353 ◽  
pp. 1416-1419
Author(s):  
You Ning Xu ◽  
Hai Zhao ◽  
Duo Jiao Guan
Keyword(s):  
Electron Microscopy ◽  
Precipitation Method ◽  
Nanosized Particles ◽  
X Ray Diffraction ◽  
Scr Catalyst ◽  
X Ray ◽  
Surface Areas ◽  
Transmission Electron ◽  
Sulfur Capacity ◽  
Co Precipitation

Fe-Mn-Ce metal oxides nanosized particles have been prepared by co-precipitation approach using three kinds of precipitants NaOH, NH4OH and Na2CO3. The products were characterized by Powder X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and BET study. It was found that the samples prepared with NH4OH as a precipitator show higher surface areas and larger sulfur capacity at low calcinations temperature. At high reaction temperatures, the samples prepared with Na2CO3 as precipitator exhibited much better activities for SCR of nitric oxide with ammonia than catalysts prepared with NH4OH and NaOH as the precipitants.

scholarly journals Structural Analysis using X-Ray Diffraction and FTIR Spectroscopic Studies on Mn2+ Substituted CaWO4 Materials Synthesized by Coprecipitation Method

2019 ◽  
Vol 32 (1) ◽  
pp. 49-52
Author(s):  
M. Jaganadha Rao ◽  
K.S.R. Murthy ◽  
Ch. Ravi Shankar Kumar ◽  
Anjali Jha ◽  
G.S.V.R.K. Choudary ◽  
...  
Keyword(s):  
Crystallite Size ◽  
Point Group ◽  
Size Composition ◽  
Spectroscopic Studies ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Patterns ◽  
Co Precipitation ◽  
Synthesis Of Materials

Present day technology requires synthesis of materials with low energy consumption, free mercury pollution and its reliability. A novel material with control of crystallite size, composition and simple for white light relies in synthesis of materials. The present focus of article attributes series of manganese doped Ca1-xMnxWO4 luminescent materials with co-precipitation method. Reported studies attempts with change in structure of calcium tungstate (CaWO4) are observed with dopants like Eu3+, Eu2+, Tb3+, etc. However the effect of Mn2+ on structural properties of CaWO4 are quite interesting. The synthesized samples were characterized with X-ray diffraction for lattice parameters, crystallite size and FTIR studies for bonding mechanism of O-W-O stretching and W-O-W bridge bond. Rietveld profile refinement of XRD patterns using MAUD program Ca1-xMnxWO4 revealed the Scheelite type structure with C4h point group and I41/a space group. Characterization studies reveal that doping of Mn2+ doping upto 0.1 in place of Ca2+ will not change the phase of Scheelite structure.

XRD Studies on Transformation of Dolomite under CO2 and N2 Atmosphere

2020 ◽  
Vol 1010 ◽  
pp. 355-360
Author(s):  
Siti Sarahah Sulhadi ◽  
Maratun Najiha Abu Tahari ◽  
Salma Samidin ◽  
Wan Nor Roslam Wan Isahak ◽  
Muhammad Rahimi Yusop ◽  
...  
Keyword(s):  
High Temperature ◽  
Crystallite Size ◽  
Fluidized Bed ◽  
Chemical Reactions ◽  
Fluidized Bed Reactor ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Xrd Studies ◽  
Significant Chemical

In this study, dolomite was heated under CO2 and N2 gases using fluidized bed reactor from 85 °C to 835 °C. Dolomite under N2 atmosphere did not show any significant changes on its crystallite size, suggesting there is no significant chemical reaction. On the other hand, dolomite under CO2 atmosphere shows no significant changes on its crystallite size until it reaches high temperature (> 800 °C) where MgO started to be observed in X- ray diffraction. This shows that few chemical reactions started to happen in this reaction condition.

Nanophase Copper Ferrite Using an Organic Gelation Technique

1996 ◽  
Vol 457 ◽  
Author(s):  
D. Sriram ◽  
R. L. Snyder ◽  
V. R. W. Amarakoon
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Crystallite Size ◽  
Polyacrylic Acid ◽  
Size Analysis ◽  
Copper Ferrite ◽  
Carboxylic Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nano Size

ABSTRACTNanocrystalline copper ferrite (Cu0.5Fe2.5O4) was synthesized using a forward strike gelation method with polyacrylic acid (PAA) as a gelating agent. The dried gel was calcined at a low temperature of 400 °C to get the final powder. The effect of pH and the ratio of the cation to the carboxylic group in the initial gel were studied with respect to both the phases and the crystallite size of the final powders synthesized. Phase and crystallite size analysis were done using x-ray diffraction and TEM. Saturation magnetization results were obtained using a SQUID magnetometer. The reactions occurring in the nano-size copper ferrite, in air as a function of temperature, were tracked using adynamic high temperature x-ray diffraction (HTXRD) system.

scholarly journals Resolving the effects of 2D versus 3D grain measurements on (U-Th)/ He age data and reproducibility

2019 ◽  
Author(s):  
Emily H. G. Cooperdock ◽  
Richard A. Ketcham ◽  
Daniel F. Stockli
Keyword(s):  
Surface Area ◽  
Ct Scanning ◽  
Cost Effective ◽  
X Ray ◽  
Surface Areas ◽  
Two Samples ◽  
Sphere Radius ◽  
Precise Quantification ◽  
Ct Data ◽  
Sample Age

Abstract. (U-Th)/He thermochronometry relies on accurate and precise quantification of individual grain volume and surface area, which are used to calculate mass, alpha ejection (FT) correction, isotope concentrations, equivalent sphere radius (ESR), and ultimately age. The vast majority of studies use 2D or 3D microscope dimension measurements and an idealized grain shape to calculate these parameters, and a long-standing question is how much uncertainty these assumptions contribute to observed intra-sample age dispersion and accuracy. Here we compare the results for volume, surface area, grain mass, ESR, effective uranium (eU) and FT correction derived from 2D microscope and 3D x-ray computed tomography (CT) length and width data for > 100 apatite grains. We analyzed apatite grains from two samples that exhibited a variety of crystal habits, some with inclusions. We also present 83 new apatite (U-Th)/He ages to assess the influence of 2D versus 3D FT correction on sample age precision. The data illustrate that the 2D approach systematically overestimates grain volumes and surface areas by 20–25 %, impacting the estimates for mass, eU, and ESR – all important parameters used for interpreting age scatter and inverse modeling. FT factors calculated from 2D and 3D measurements differ by ~ 2 %. This variation, however, has effectively no impact on reducing intra-sample age reproducibility. We also present a grain mounting procedure for x-ray CT scanning that can allow 100's of grains to be scanned in a single session, and new software capabilities for 3D FT and FT-based ESR calculations that are robust for relatively low-resolution CT data, that together enable efficient and cost-effective CT-based characterization.

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