scholarly journals Preparation of Nanosized LaCoO3through Calcination of a Hydrothermally Synthesized Precursor

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
L. Tepech-Carrillo ◽  
A. Escobedo-Morales ◽  
A. Pérez-Centeno ◽  
E. Chigo-Anota ◽  
J. F. Sánchez-Ramírez ◽  
...  
Keyword(s):  
Perovskite Phase ◽  
Reaction Times ◽  
Precursor Powder ◽  
Dehydration Process ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Calcination Temperatures ◽  
Lanthanum Oxides ◽  
Scanning Electron

A method for obtaining nanosized LaCoO3crystals from calcination of a precursor powder synthesized by a hydrothermal route is reported. Details concerning the evolution of the microstructure and formation mechanism of the perovskite phase were studied by powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, and thermal analysis. It was found that the morphology of the sample progressively turns from a mix of fibers and rods to interconnected nanocrystals. It is determined that LaCoO3phase is produced by a reaction of cobalt and lanthanum oxides, the latter produced by a two-step dehydration process of La(OH)3. Finally, it was found that nearly stoichiometric LaCoO3nanocrystals can be obtained at temperatures as low as 850°C. Nevertheless, whether higher calcination temperatures are used, appropriate reaction times and a controlled atmosphere are required in order to avoid formation of lanthanum carbonates and high density of lattice defects.

Fabrication of Lead Barium Titanate Ceramics via Conventional Solid-State Mixed Oxide Technique

2008 ◽  
Vol 55-57 ◽  
pp. 209-212 ◽  
Author(s):  
Theerachai Bongkarn ◽  
P. Panya
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Mixed Oxide ◽  
Perovskite Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcination Temperatures ◽  
Grain Sizes ◽  
Titanate Ceramics ◽  
Scanning Electron

(Pb0.925Ba0.075)TiO3 (PBT) ceramics have been prepared using a mixed oxide technique. The phase formation and morphology were studied in detail via X-ray diffraction (XRD) and scanning electron microscopy (SEM). The pure tetragonal perovskite structure was discovered with calcination temperatures above 800 oC. The percentage of perovskite phase and particle size tends to increase with the increasing of calcination temperatures. The PBT ceramics sintered at various temperatures belonged to a pure tetragonal perovskite phase. The average grain sizes increased from 0.90 to 6.44 µm with the increase of sintering temperatures from 1100 to 1200 oC. The highest density was obtained from the sample that sintered at 1150 and 1200 oC

Cryogenically Synthesized Mechanically Alloyed Calcia Stabilized Zirconia

2009 ◽  
Vol 67 ◽  
pp. 271-276 ◽  
Author(s):  
Raja Ram Prasad ◽  
B.S. Sunder Daniel
Keyword(s):  
Electron Microscopy ◽  
Phase Evolution ◽  
Precursor Powder ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Mechanically Alloyed ◽  
X Ray ◽  
Precursor Powders ◽  
Cryogenic Conditions ◽  
Scanning Electron

Precursor powder of calcia-stabilized zirconia (CSZ) with 4, 7 and 15 wt % was synthesized by mechanical alloying (MA) in cryogenic conditions. The phase evolution of the precursor powders over 100 hours of MA was analyzed by powder X-ray diffraction technique. Cylindrical shaped sensor elements of the calcined powders were fabricated in a uniaxial press followed by sintering at 15000C for 3 hours. Scanning electron microscopy (SEM) was used to analyze the microstructure of the sintered pellets. The co-relation between material compositions, microstructure of the sinter pellets and the electrical properties of the sensors are discussed.

Effects of Mg2+ Doping on the Properties of LiFePO4 Synthesized via Hydrothermal Route

2009 ◽  
Vol 610-613 ◽  
pp. 498-501
Author(s):  
Guang Chuan Liang ◽  
Xiao Ke Zhi ◽  
Xiu Qin Ou ◽  
Li Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
Cell Volume ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Charge Discharge ◽  
Scanning Electron ◽  
Discharge Test

Mg2+ doped LiFePO4 was synthesized from Li3PO4, FeSO4 and MgSO4 by a hydrothermal synthesis at 150 °C（Li1-xMgxPO4, x=0.00, 0.01,0.02,0.04,0.06）. The samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and charge-discharge test. The results showed that Mg2+ dissolved in the LiFePO4 lattice. When the content is in the range of 0 to 6 mol%, Mg2+ caused the shrinkage of LiFePO4 cell volume. The capacity of doped and undoped samples at low discharging rate was similar, about 145mAhg-1 for 0.2C. But the sample doped with 2-4 mol% Mg2+ has higher capacity and longer cycle lifetime than the undoped one at 5C.

scholarly journals Effects of Calcination Temperatures on Photocatalytic Activity of Ordered Titanate Nanoribbon/SnO2Films Fabricated during an EPD Process

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Li Zhao ◽  
Jingrun Ran ◽  
Zhan Shu ◽  
Guotian Dai ◽  
Pengcheng Zhai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phase Transformation ◽  
Photocatalytic Activity ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcination Temperatures ◽  
Fto Glass ◽  
Scanning Electron

Ordered titanate nanoribbon (TNR)/SnO2films were fabricated by electrophoretic deposition (EPD) process using hydrothermally prepared titanate nanoribbon as a precursor. The formation mechanism of ordered TNR film on the fluorine-doped SnO2coated (FTO) glass was investigated by scanning electron microscopy (SEM). The effects of calcination temperatures on the phase structure and photocatalytic activity of ordered TNR/SnO2films were investigated and discussed. The X-ray diffraction (XRD) results indicate that the phase transformation of titanate to anatase occurs at 400°C and with increasing calcination temperature, the crystallization of anatase increases. At 600°C, the nanoribbon morphology still hold and the TiO2/SnO2film exhibits the highest photocatalytic activity due to the good crystallization, unique morphology, and efficient photogenerated charge carriers separation and transfer at the interface of TiO2and SnO2.

Hydrothermal Synthesis of Zinc Oxide (ZnO) Microparticle

2008 ◽  
Vol 55-57 ◽  
pp. 845-848 ◽  
Author(s):  
Pusit Pookmanee ◽  
S. Khuanphet ◽  
Sukon Phanichphant
Keyword(s):  
Zinc Oxide ◽  
Single Phase ◽  
Ammonium Hydroxide ◽  
Hexagonal Structure ◽  
Deionized Water ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Calcination Step ◽  
Scanning Electron

Zinc oxide (ZnO) microparticle was synthesized by hydrothermal route using zinc acetate and ammonium hydroxide as the starting precursors in the mole ratio of 1:6. The final mixture solution was adjust with pH of 9 and treated in PTFE-line autoclave at 100 oC for 2, 4 and 6 h. The precipitate was washed with deionized water until the final pH solution of 7 and then dried at 100 oC for 4h. The phase structure was examined by X-ray diffraction (XRD). A single phase hexagonal structure was obtained without calcination step. Microstructure was investigated by scanning electron microscopy (SEM). The particle size of ZnO was in the range of 0.15-1.5 µm with irregular in shape. The chemical composition was identified by energy dispersive X-ray spectroscopy (EDXS). The elemental composition of ZnO showed the characteristic X-ray energy value as follows: zinc of Lα = 1.012 keV, Kα = 8.630 keV and Kβ = 9.570 keV and oxygen of Kα = 0.525 keV, respectively.

scholarly journals One-Pot Access to Diverse Functionalized Pyran Annulated Heterocyclic Systems Using SCMNPs@BPy-SO3H as a Novel Magnetic Nanocatalyst

2020 ◽  
Vol 15 (2) ◽  
pp. 348-366 ◽  
Author(s):  
Ke Chen ◽  
Guangzu He ◽  
Qiong Tang ◽  
Qahtan A.Yousif
Keyword(s):  
Magnetic Field ◽  
Reaction Times ◽  
Vibrating Sample Magnetometry ◽  
X Ray Diffraction ◽  
Magnetic Nanocatalyst ◽  
Permanent Magnetic Field ◽  
One Pot ◽  
X Ray ◽  
The One ◽  
Scanning Electron

The SCMNPs@BPy-SO3H catalyst was prepared and characterized using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Vibrating Sample Magnetometry (VSM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Afterwards, its capability was efficiently used to promote the one-pot, three-component synthesis of pyrano[2,3-c]pyrazole and 2-amino-3-cyano-pyrano[3,2-c]chromen-5(4H)-one derivatives. The strategy resulted in the desired products with excellent yields and short reaction times. The SCMNPs@BPy-SO3H catalyst was readily recovered using a permanent magnetic field and it was reused in six runs with a slight decrease in catalytic activity. Copyright © 2020 BCREC Group. All rights reserved 

Synthesis and Characterization of NiO Doped SnO2 Nano-Flowers

2013 ◽  
Vol 575-576 ◽  
pp. 58-60
Author(s):  
Wei Ping Tang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectrum ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Hydrothermal Route ◽  
X Ray ◽  
Scanning Electron

In this present work, a new method for preparing NiO doped SnO2 nanoflowers by hydrothermal route is suggested. The composition and microstructure of samples were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and Fourier transform infrared spectrum (FTIR). Moreover, a possible formation mechanism was discussed.

Effect of Oxidation on Phase Transformation in Ti-Bearing Blast Furnace Slag

2013 ◽  
Vol 641-642 ◽  
pp. 363-366 ◽  
Author(s):  
Wu Zhang ◽  
Li Zhang ◽  
Nai Xiang Feng
Keyword(s):  
Phase Transformation ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Glass Phase ◽  
Perovskite Phase ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Furnace Slag ◽  
Scanning Electron

Abstract. Effect of oxidation on phase transformation in Ti-bearing blast furnace slag is studied. The slag is analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM), EDX and metallographic microscope. The experiment results indelicate that the phase composition of the oxidized slag is simpler which are only rutile and glass phase. The titanaugite, Ti-rich diopside and perovskite phase are vanished and most of the Ti components were enriched in the rutile phase.

Preparation and Characterization of Perovskite Pb(Mg1/3Nb2/3)O3-PbTiO3 by a Modified Polymerized Complex Process

2008 ◽  
Vol 368-372 ◽  
pp. 30-32 ◽  
Author(s):  
Jin Chen ◽  
Hui Qing Fan ◽  
Shao Jun Qiu
Keyword(s):  
Lead Acetate ◽  
Perovskite Phase ◽  
Pyrochlore Phase ◽  
Phase Evolution ◽  
Complex Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Complex Process ◽  
Scanning Electron

Relaxor-based ferroelectrics, 0.65Pb(Mg1/3Nb2/3)O3-0.35PbTiO3 (PMN-PT) with a pyrochlore-free phase, was prepared by a modified polymerized complex process. The reactive columbite (MgNb2O6) phase was synthesized by the polymerized complex method at 1050oC for 4 h with 3wt% excess MgO. Lead acetate and tetrebutyl titanate were used to synthesize pyrochlore-free PMN-PT powder via the columbite route, from 800oC to 900oC, in air for 4 h. X-ray diffraction and scanning electron microscopy were used to detect the perovskite phase evolution and the presence of the pyrochlore phase in PMN-PT. The formation of perovskite PMN-PT is a function of the time and temperature conditions of the precursor calcinations, and an optimum condition for the thermal decomposition of the precursor was determined to avoid the formation of the pyrochlore phase.

Catalytic CO2/H2 Methanation Reaction over Alumina Supported Manganese/Cerium Oxide Based Catalysts

2015 ◽  
Vol 1107 ◽  
pp. 67-72 ◽  
Author(s):  
Salmiah Jamal Mat Rosid ◽  
Wan Azelee Wan Abu Bakar ◽  
Rusmidah Ali
Keyword(s):  
Cerium Oxide ◽  
Supported Catalysts ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Wet Impregnation ◽  
X Ray ◽  
Methanation Reaction ◽  
Calcination Temperatures ◽  
Impregnation Technique ◽  
Scanning Electron

The methanation reaction is a promising method for the purification of natural gas, in which the acid gases of CO2,is eliminated by catalytic conversion. The advantage of catalytic technology is the utilization of CO2present in the production of methane gas. The used of alumina supported cerium oxide as the based catalyst in CO2/H2methanation reaction have been investigated in this research by using manganese as the dopant and ruthenium as the co-dopantviawet impregnation technique. The series of cerium oxide catalysts were calcined at 400 °C for 5 hours had been prepared at the screening stage. Then, the catalysts were optimized by different calcination temperatures and different based oxide loadings. The potential catalysts of Ru/Mn/Ce (5:35:60)/Al2O3calcined at 700 °C gave 100 % of CO2conversion by using FTIR and yielded about 24 % of CH4respectively at reaction temperature of 400 °C. X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) showed that the supported catalysts were amorphous in structure. FESEM analysis illustrated the surface of the catalysts were covered with small and dispersed spherical particles. EDX analysis revealed that there was 1.02 % reduction of Ru in the Ru/Mn/Ce (5:35:60)/Al2O3used catalysts compared to fresh catalysts. Meanwhile NA analysis showed that Ru/Mn/Ce (5:35:60)/Al2O3catalysts attained surface area of 143.10 m2/g respectively.

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