Cobalt Catalyst Doped with Cerium and Barium Obtained by Co-Precipitation Method for Ammonia Synthesis Process

2011 ◽  
Vol 141 (5) ◽  
pp. 678-684 ◽  
Author(s):  
Wioletta Raróg-Pilecka ◽  
Magdalena Karolewska ◽  
Elżbieta Truszkiewicz ◽  
Ewa Iwanek ◽  
Bogusław Mierzwa
Keyword(s):  
Cobalt Catalyst ◽  
Ammonia Synthesis ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Co Precipitation

Effect of the Synthesis Method on the Properties of Ultrafine YAG Powder

2018 ◽  
Vol 281 ◽  
pp. 40-45
Author(s):  
Jie Guang Song ◽  
Lin Chen ◽  
Cai Liang Pang ◽  
Jia Zhang ◽  
Xian Zhong Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Hydrothermal Reaction ◽  
Synthesis Method ◽  
Particle Morphology ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Powder Materials ◽  
Co Precipitation

YAG materials has a number of unique properties, the application is very extensive. In this paper, the superfine YAG powder materials were prepared by co-precipitation method and hydrothermal precipitation method. The influence of synthesis process on the morphology of the powder was investigated. The results showed that the precursor powder prepared via the co-precipitation method is mainly from amorphous to crystalline transition with the increasing calcination temperature, the precursor agglomeration is more serious, In the process of increasing the calcination temperature, the dispersibility of the roasted powder is greatly improved, which is favorable for the growth of the crystal grains, so that the particle size of the powder is gradually increased, the YAG precursor prepared by the co-precipitation method is transformed into YAG crystals, the phase transition occurs mainly between 900 and 1100°C. When the molar ratio of salt to alkali is Y3+: OH-=1: 8 via the hydrothermal reaction, the YAG particles with homogeneous morphology can be obtained. When the molar ratio of salt and alkali is increased continuously, the morphology of YAG particles is not obviously changed. The co-precipitation method is easy to control the particle size, the hydrothermal method is easy to control the particle morphology.

scholarly journals Synthesis and Characterization of the CaTiO3:Eu3+ Red Phosphor by an Optimized Microwave-Assisted Sintering Process

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 874
Author(s):  
Haifeng Wang ◽  
Jianwei Lu ◽  
Ruoxuan Wang ◽  
Yungu Dong ◽  
Linfeng Ding
Keyword(s):  
Red Light ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Sintering Process ◽  
Time Saving ◽  
Red Phosphor ◽  
Microwave Assisted ◽  
Furnace Sintering ◽  
Co Precipitation

The synthesis process has a significant influence on the properties of Ca1-xTiO3:Eu3+x phosphors; thus, an optimized process will lead to a better performance of the Ca1-xTiO3:Eu3+x phosphors. In this work, the feasibility of synthesizing the Ca1-xTiO3:Eu3+x phosphor with a good luminescent performance by combining the chemical co-precipitation method and microwave-assisted sintering was studied. The precursor of Ca1-xTiO3:Eu3+x phosphors were prepared by the chemical co-precipitation method. To find an optimized process, we applied both of the traditional (furnace) sintering and the microwave-assisted sintering to synthesize the Ca1-xTiO3:Eu3+x phosphors. We found out that a sintering power of 528 W for 50 min (temperature around 950 °C) by a microwave oven resulted in similar emission intensity results compared to traditional furnace sintering at 900 °C for 2.5 h. The synthesized Ca1-xTiO3:Eu3+x phosphors has an emission peak at 617 nm (5D0→7F2), which corresponds to the red light band. This new synthesized method is an energy efficient, time saving, and environmentally friendly means for the preparation of Ca1-xTiO3:Eu3+x red phosphor with good luminescent performance.

Synthesis Conditions of Nano-Hydroxyapatite Using Chondroitin Sulfate by Co-Precipitation Method

2011 ◽  
Vol 236-238 ◽  
pp. 2076-2079
Author(s):  
Yan Rong Sun ◽  
Tao Fan ◽  
Yong Huang ◽  
Li Guo Ma ◽  
Feng Liu
Keyword(s):  
Chondroitin Sulfate ◽  
Ph Value ◽  
Orthogonal Design ◽  
Precipitation Method ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Powder Morphology ◽  
Synthesis Conditions ◽  
Transmission Electron ◽  
Co Precipitation

The introduction of biomineralization was coupled with the co-precipitation synthesis process of nano-hydroxyapatite with the addition of chondroitin sulfate as a template agent. The effect of a variety of processing conditions on the properties of final hydroxyapatite (HA) product was investigated by orthogonal design. The ratio of calcium to phosphorus was detected by chemical analysis, the phase composition was evaluated by X-ray diffraction (XRD), and the powder morphology was characterized by transmission electron microscope (TEM). The process scheme, moreover, was optimized by the analysis of four aspects which may have different extent of influence on product properties. It can be concluded from the results that product properties can be affected remarkably by the content of chondroitin sulfate and the pH value of reactant, less remarkably by the reaction temperature and slightly by the reaction time.

Physical and Optical Properties of Indium Oxide: Tin Nanoparticles Synthesized by Co-Precipitation Method

2015 ◽  
Vol 659 ◽  
pp. 604-608 ◽  
Author(s):  
Jiruntanin Kanoksinwuttipong ◽  
Wisanu Pecharapa ◽  
Russameeruk Noonuruk ◽  
Wicharn Techitdheera
Keyword(s):  
Optical Properties ◽  
Single Phase ◽  
Precipitation Method ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Optical Absorbance ◽  
Molar Ratios ◽  
Tin Nanoparticles ◽  
Ion Substitution ◽  
Co Precipitation

Indium oxide:tin nanoparticles were synthesized by co-precipitation method using InCl3 and SnCl4·5H2O as starting precursor with different molar ratios of Sn:In. The crystalline structure, optical properties, chemical bonding and morphologies of all samples were characterized by X-ray diffraction (XRD), UV–vis spectrometer, Raman spectroscopy and field emission scanning electron microscope, respectively. The XRD results show that the crystallinity of as-synthesized powders was initially amorphous phase. After calcination at 400 °C for 2 h, a single phase ITO powder with 10% (mol%) SnO2 was obtained. The particle size of each sample is approximately 20-25 nm. The color of indium oxide:tin nanopowders after heat treatment changed from white to yellow due to the substitution of oxygen vacancies in the sample. After calcination, the intensity of Raman peak significantly decreased with increasing amount of Sn loading. This phenomenon indicates that ion substitution may occur during the synthesis process. Moreover, it is noticed that the optical absorbance of obviously changed with increasing Sn loading.

scholarly journals Investigation on Variables Contributing to the Synthesis of C-S-H/PCE Nanocomposites by Co-Precipitation Method

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7673
Author(s):  
Ziyang You ◽  
Jing Xu
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Orthogonal Experimental Design ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Ultra Fine Particle ◽  
Early Performance ◽  
Co Precipitation

The usage of nanoscale calcium silicate hydrate (nano C-S-H) proved to have an excellent promotion effect on the early performance of concrete as nano C-S-H with ultra-fine particle size can act as seeding for cement hydration. Therefore, it is of importance to tune the particle size during the synthesis process of nano C-S-H. In this paper, the influence of several variables of the particle size distribution (PSD) of nano C-S-H synthesized by chemical co-precipitation method with the aid of polycarboxylate (PCE) was studied by orthogonal experimental design. In addition, the composition, microstructure, and morphology of the C-S-H/PCE nanocomposites were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectrum. The results showed that the concentration of reactants had a significant impact on the PSD of C-S-H/PCE nanocomposites, followed by the dosage of dispersant. Ultrasonic treatment was effective in breaking the C-S-H/PCE aggregates with unstable agglomeration structures. The change in synthetic variables had a negligible effect on the composition of the C-S-H/PCE nanocomposites but had a significant influence on the crystallinity and morphology of the composites.

scholarly journals Effect of NaOH concentration on optical properties of zinc oxide nanoparticles

2016 ◽  
Vol 34 (4) ◽  
pp. 819-827 ◽  
Author(s):  
Vaibhav Koutu ◽  
Lokesh Shastri ◽  
M. M. Malik
Keyword(s):  
Raman Spectroscopy ◽  
Zinc Oxide ◽  
Optical Properties ◽  
Zno Nanoparticles ◽  
Visible Spectrum ◽  
Hexagonal Wurtzite Structure ◽  
Peak Shift ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Co Precipitation

AbstractIn the present work, powder zinc oxide samples were prepared by varying NaOH concentration (0.1 M – 0.4 M) using wet-chemical co-precipitation method. As-synthesized ZnO was characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), photoluminescence (PL) and Raman spectroscopy. Formation of hexagonal wurtzite structure of the ZnO samples has been revealed from XRD studies. This study further suggests reduction in crystallite size from 40 nm to 23 nm with an increase in NaOH concentration which is confirmed by FESEM. PL and Raman spectroscopy studies of these samples show significant peak shift towards the higher and lower energy respectively, with maximum PL emission between 400 nm and 470 nm region of the visible spectrum. Noticeable inverse relationship between optical properties of ZnO nanoparticles and NaOH concentration may be attributed to the rapid nucleation during the synthesis process. With these remarkable properties, ZnO nanoparticles may find applications in nanoelectronic devices, sensors, nanomedicine, GATE dielectrics, photovoltaic devices, etc.

scholarly journals Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis

2017 ◽  
Vol 12 (3) ◽  
pp. 357
Author(s):  
Muhammad Faizan Shareef ◽  
Muhammad Arslan ◽  
Naseem Iqbal ◽  
Nisar Ahmad ◽  
Tayyaba Noor
Keyword(s):  
Cobalt Catalyst ◽  
Synthesis Method ◽  
Fixed Bed ◽  
Tropsch Synthesis ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Co Catalysts ◽  
Co Precipitation

This paper presents the effect of a synthesis method for cobalt catalyst supported on hydrotalcite material for Fischer-Tropsch synthesis. The hydrotalcite supported cobalt (HT-Co) catalysts were synthesized by co-precipitation and hydrothermal method. The prepared catalysts were characterized by using various techniques like BET (Brunauer–Emmett–Teller), SEM (Scanning Electron Microscopy), TGA (Thermal Gravimetric Analysis), XRD (X-ray diffraction spectroscopy), and FTIR (Fourier Transform Infrared Spectroscopy). Fixed bed micro reactor was used to test the catalytic activity of prepared catalysts. The catalytic testing results demonstrated the performance of hydrotalcite based cobalt catalyst in Fischer-Tropsch synthesis with high selectivity for liquid products. The effect of synthesis method on the activity and selectivity of catalyst was also discussed. Copyright © 2017 BCREC Group. All rights reservedReceived: 3rd November 2016; Revised: 26th February 2017; Accepted: 9th March 2017; Available online: 27th October 2017; Published regularly: December 2017How to Cite: Sharif, M.S., Arslan, M., Iqbal, N., Ahmad, N., Noor, T. (2017). Development of Hydrotalcite Based Cobalt Catalyst by Hydrothermal and Co-precipitation Method for Fischer-Tropsch Synthesis. Bulletin of Chemical Reaction Engineering & Catalysis, 12(3): 357-363 (doi:10.9767/bcrec.12.3.762.357-363) 

scholarly journals Morphology control of SrBi2Nb2O9 prepared by a modified chemical method

2019 ◽  
Vol 51 (4) ◽  
pp. 353-361
Author(s):  
Mohamed Afqir ◽  
Amina Tachafine ◽  
Didier Fasquelle ◽  
Mohamed Elaatmani ◽  
Jean-Claude Carru ◽  
...  
Keyword(s):  
Molten Salt ◽  
Reaction Medium ◽  
Precipitation Method ◽  
Molten Salt Synthesis ◽  
Synthesis Process ◽  
Strontium Nitrate ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Co Precipitation

SrBi2NbO9 compounds were prepared through three methods: oxalate co-precipitation, molten salt synthesis and polymerizable complex. The effect of the molecular precursor route has also been investigated. For oxalate co-precipitation method, a solution obtained from acid oxalate, niobium oxide, bismuth nitrate and strontium nitrate are precipitated by ammoniac solution. Then, the precipitated sample is calcined at 1100?C. A methanol-citric acid solution of solution of NbCl5, ethylene glycol, bismuth and strontium nitrates were used as precursors. A black powder ash was crystallized by heat-treating at 1100?C. Molten salt technique using oxides and carbonate as starting materials and NaCl and KCl to form a reaction medium. The formation temperature was at 1110?C. Multiple characterizations mainly X-ray diffraction, Fourier transformed infrared spectroscopy and scanning electron microscopy (SEM) measurements have provided to validate the structural feature. Careful, X-ray diffraction analysis showed the presence of two-layered Aurivillius structure. The crystallite size is discussed by Scherrer and Williamson-Hall approaches. SEM images of SrBi2NbO9 ceramics showed plate-like, polygonal and structureless morphologies obtained at different synthesis conditions. Whatever the synthesis process, there is no change on the band of infrared spectra.

scholarly journals A study on synthesis and characterization of Dy-dopedLa0.6Sr0.4Co0.2Fe0.8O3-δvia co precipitation method

2020 ◽  
Author(s):  
Negin Mohammadi ◽  
Zahra Khakpour ◽  
Amir Maghsoudipour ◽  
Aida Faeghinia
Keyword(s):  
Phase Formation ◽  
Perovskite Phase ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Average Particle ◽  
Powder Morphology ◽  
Co Precipitation

Abstract The perovskite Lanthanum Strontium Cobalt Ferrite (LSCF) is investigated as the cathode material used in intermediate temperature solid oxide fuel cells (IT-SOFCs). In the present study, La0.6-xDyxSr0.4Co0.2Fe0.8O3-δ(x= 0, 0.3, 0.6) was synthesized through co precipitation method. The obtained precipitate was calcined at500, 700,900and 1000°С. Phase characterization of synthesized LSCF and LDySCF powder before and after heat treatment at 700°Сwas carried out by X-ray diffraction (XRD) analysis. XRD patterns revealed that the perovskite phase was obtained at 700 °С in all calcined samples. Chemical bond study to investigate synthesis process was done using the Fourier transform infrared spectroscopy technique. Thermalanalysis of DTA and TG has been utilized to investigate how the calcination temperature affects the peroveskite phase formation. According to the STA results, the perovskite phase formation started at 551°Сafterwarditcompleted at 700°С.The density values of synthesized powders were 6.10, 6.11 and 6.37g.cm-3for the undoped and doped samples calcined at 700°С. Powder morphology was studied by Field emission scanning electron microscopy. (FE-SEM) micrographs showed the spherical shaped particles with the average particle size of 24-131nm.

Preparation of Transparent Nd:Gd2O3-HfO2 Ceramic

2008 ◽  
Vol 368-372 ◽  
pp. 432-434
Author(s):  
Tao Feng ◽  
Jian Lin Shi ◽  
Hai Fang Xu ◽  
Dan Yu Jiang
Keyword(s):  
Heat Capacity ◽  
Optical Properties ◽  
Solid State ◽  
Powder Compact ◽  
Transparent Ceramic ◽  
Precipitation Method ◽  
Synthesis Process ◽  
Laser Material ◽  
State Heat ◽  
Co Precipitation

Nd:Gd2O3-HfO2 powder has been prepared with a co-precipitation method. The size of Nd:Gd2O3-HfO2 powder is near 50nm. Transparent Nd:Gd2O3-HfO2 ceramics were successfully fabricated by sintering the powder compact at 1800°C under H2 atmosphere. The synthesis process and optical properties were investigated in detail. By measuring the optical properties of transparent Nd:Gd2O3-HfO2 ceramics, we found that the absorption bond of Nd ions near 808nm is enlarged, and the FWHM of the emission bond near 1060nm is near 25nm. It was believed that Nd:Gd2O3-HfO2 transparent ceramic is potential laser material for the usage in solid-state heat-capacity laser(SSHCL) application.

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