The Effect of Preparation Method of Precursor on Synthesis of BiFeO3 by a Hydrothermal Method

2014 ◽  
Vol 906 ◽  
pp. 178-182
Author(s):  
Yang Xiao ◽  
Zhen Zhu Cao ◽  
Ru Yi Shao ◽  
Wei Yan He ◽  
Yan Fang Gao ◽  
...  
Keyword(s):  
Reaction Time ◽  
Hydrothermal Method ◽  
Influencing Factors ◽  
Preparation Method ◽  
Raw Materials ◽  
Bismuth Ferrite ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Precipitation Process ◽  
Co Precipitation

The precursor of bismuth ferrite BiFeO3 powders were prepared by the normal co-precipitation and reversed co-precipitation method. The key influencing factors including the reaction time, the concentration of mineralizer and the molar ratio of raw materials in the normal co-precipitation are systematically studied. Pure BiFeO3 powder has been obtained by adjusting the molar ratio of raw materials. Based on the results of the normal co-precipitation, a simple reversed co-precipitation process has been developed.

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 Optimization analysis of separation conditions of washed water containing a lead complex and characterization of the precipitation products

2017 ◽  
Vol 76 (12) ◽  
pp. 3220-3226 ◽  
Author(s):  
Wenmin Cai ◽  
Jiajun Chen ◽  
Qingwei Wang ◽  
Meng Wei
Keyword(s):  
Reaction Time ◽  
Environmental Governance ◽  
Sodium Sulfide ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Precipitation Process ◽  
Process Conditions ◽  
Precipitation Reaction ◽  
Reaction Products ◽  
X Ray Diffraction

Abstract Presently, the large amount of industrial leaded wastewater creates a great challenge to both environmental governance and wastewater recycling. Lead complexes in washed water must be removed mostly before the washed water can be recycled. This paper reports the mechanism and factors of removing Pb complexes in simulated washed water by the sulfide precipitation method. The reaction time, sodium sulfide dosage, pH, and polymeric aluminum chloride (PAC) dosage were analyzed and the optimal conditions were explored. The composition of the reaction products was also verified by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Additionally, the kinetics of the precipitation reaction of sodium sulfide and Pb-EDTA were studied. These results showed that the Pb removal efficiency reached 91.7% under the optimal process conditions which were as follows: the dosages of Na2S and PAC were 188 mg/L (Na2S/Pb2+ molar ratio of 5:1) and 30 mg/L, respectively, the reaction time was 40 min, and the pH was 9. It was demonstrated using SEM and XRD that the reaction product in the separation process was PbS and the precipitation process was fitted to the following first-order reaction kinetics equation: Ct = 89.1e−0.1047t + 10.1 (R2 = 0.9929; Ct is Pb concentration at reaction time t).

Influences of Preparation Parameters of Catalyst Support on the SCR Denitration Activity of Mn-Ce/TiO2

2016 ◽  
Vol 697 ◽  
pp. 279-283
Author(s):  
Yan Xia Wu ◽  
Hai Long Liang ◽  
Xin Chen ◽  
Jie Tang ◽  
Yu Feng Chen ◽  
...  
Keyword(s):  
Active Component ◽  
Preparation Method ◽  
Catalyst Support ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Active Components ◽  
No Removal ◽  
Denitrification Activity ◽  
Co Precipitation

The catalytic performance of NO removal was studied over Mn-Ce/TiO2 catalysts prepared by different preparation parameters, such as preparation method, Ce/(Mn+Ce) molar ratio and calcination temperature. It was found that samples prepared by co-precipitation method, which had the largest surface area and highly dispersed active component particles, showed the best denitrification activity. The highest NO conversion of 95% is achieved at the Ce/(Mn+Ce) molar ratio of 15% which is much higher than that of the pure manganese constituent. The increase of calcining temperature favored the crystallization of active components, leading to the decline of catalytic activity.

Luminescence of Cu2+-Doped ZnSe Quantum Dots with Different Parameters

2010 ◽  
Vol 148-149 ◽  
pp. 1268-1272 ◽  
Author(s):  
Qun Wang ◽  
Fu Tian Liu ◽  
Qing Hui Jiang ◽  
Xiu Xiu Chen ◽  
Dong Zhi Wang
Keyword(s):  
Quantum Dots ◽  
Reaction Time ◽  
Aging Time ◽  
Green Emission ◽  
Average Diameter ◽  
Transmission Electron Microscopy Image ◽  
Precipitation Method ◽  
Molar Ratio ◽  
High Fluorescence ◽  
Co Precipitation

Cu2+-doped ZnSe quantum dots (ZnSe:Cu2+ QDs) are synthesized in aqueous solution via a co-precipitation method with thioglycolic acid (TGA) as a stabilizer. Green emission is observed under 365 nm UV excitation. X-ray diffraction patterns and transmission electron microscopy image show that ZnSe:Cu2+ QDs are sphalerite cubic structure, similar to round in shape, the average diameter is 6 nm. The concentration of Cu2+ ions and TGA, pH, reaction time and aging time have influences on optical properties of ZnSe:Cu2+ QDs. The luminescence of as-prepared products with different parameters is characterized using fluorescence spectrophotometer. The high fluorescence intensity has been got when the concentration of Cu2+ ions is 4.0% (molar ratio), TGA is 83.4 μl (mol ratio Zn: TGA=1:2), pH is 9.5, reaction time is 2h. The luminous intensity increases with the extension of aging time.

A novel separation method of the valuable components for activated clay production wastewater

2021 ◽  
Vol 19 (1) ◽  
pp. 530-540
Author(s):  
Lvshan Zhou ◽  
Tongjiang Peng ◽  
Hongjuan Sun ◽  
Dong Fu ◽  
Chuan Lai
Keyword(s):  
Aluminum Phosphate ◽  
Iron Phosphate ◽  
Acid Sites ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Precipitation Process ◽  
Iron Aluminum ◽  
Phosphorus Iron ◽  
Optimized Conditions ◽  
Acidic Wastewater

Abstract The acidic wastewater produced by the wet production of activated clay contains valuable components such as iron and aluminum. The precipitation method was successfully introduced to separate iron and aluminum from the activated clay production wastewater step by step, which can not only recover the valuable components, but also avoid environmental pollution. In the separation process, gypsum, iron aluminum phosphate, alumina, and sodium sulfate were prepared, and the phase compositions of separation products were analyzed by XRD and IR. The main influencing factors in the separation of iron and aluminum components were studied by single factor experiment. The results show that at the optimized conditions, phosphorus/iron molar ratio 6.0, the system pH 3.0, the reaction temperature 343 K, and the reaction time 90 min, the iron(iii) ion in the system can form a sodium-containing aluminum iron phosphate double salt, and the filtrate after separating Fe3+ and part of Al3+ can meet the requirements for forming high-purity Al2O3. During the phosphate precipitation process, the hypothesis should be correct that Al3+ reacts with PO 4 3 − {\text{PO}}_{4}^{3-} to form an AlPO4 skeleton, Fe3+ isomorphically replaces Al3+ in the [AlO4] tetrahedron, and adsorption occurs simultaneously, with Na+ occupying the terminal acid sites, P(Al)–OH.

Effect of Fe and Co promoters on CO methanation activity of nickel catalyst prepared by impregnation – co-precipitation method

2020 ◽  
Vol 18 (5-6) ◽  
Author(s):  
Buyan-Ulzii Battulga ◽  
Tungalagtamir Bold ◽  
Enkhsaruul Byambajav
Keyword(s):  
Synergetic Effect ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Alumina Support ◽  
Co Methanation ◽  
Temperature Range ◽  
Co Precipitation ◽  
Catalyst Distribution

AbstractNi based catalysts supported on γ-Al2O3 that was unpromoted (Ni/γAl2O3) or promoted (Ni–Fe/γAl2O3, Ni–Co/γAl2O3, and Ni–Fe–Co/γAl2O3) were prepared using by the impregnation – co-precipitation method. Their catalytic performances for CO methanation were studied at 3 atm with a weight hourly space velocity (WHSV) of 3000 ml/g/h of syngas with a molar ratio of H2/CO = 3 and in the temperature range between 130 and 350 °C. All promoters could improve nickel distribution, and decreased its particle sizes. It was found that the Ni–Co/γAl2O3 catalyst showed the highest catalytic performance for CO methanation in a low temperature range (<250 °C). The temperatures for the 20% CO conversion over Ni–Co/γAl2O3, Ni–Fe/γAl2O3, Ni–Fe–Co/γAl2O3 and Ni/γAl2O3 catalysts were 205, 253, 263 and 270 °C, respectively. The improved catalyst distribution by the addition of cobalt promoter caused the formation of β type nickel species which had an appropriate interacting strength with alumina support in the Ni–Co/γAl2O3. Though an addition of iron promoter improved catalyst distribution, the methane selectivity was lowered due to acceleration of both CO methanation and WGS reaction with the Ni–Fe/γAl2O3. Moreover, it was found that there was no synergetic effect from the binary Fe–Co promotors in the Ni–Fe–Co/γAl2O3 on catalytic activity for CO methanation.

Novel Fe3O4/HNT@rGO composite via a facile co-precipitation method for the removal of contaminants from aqueous system

RSC Advances ◽  
2016 ◽  
Vol 6 (54) ◽  
pp. 49228-49235 ◽  
Author(s):  
Chengwei Gao ◽  
Baojun Li ◽  
Ning Chen ◽  
Jie Ding ◽  
Qiang Cai ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Water Treatment ◽  
Potential Application ◽  
High Performance ◽  
Aqueous System ◽  
Precipitation Method ◽  
Precipitation Process ◽  
System P ◽  
Removal Of Contaminants ◽  
Co Precipitation

Fe3O4/HNT@rGO composite (FHGC) was fabricated via a facile co-precipitation process, followed by heat treatment. For RhB and As5+removal, the high performance and easy separation of FHGC highlight its potential application in water treatment.

Preparation and Characterization of Nanocomposite Calcium Doped Ceria Electrolyte With Alkali Carbonates (NK-CDC) for SOFC

2010 ◽  
Author(s):  
Ghazanfar Abbas ◽  
Rizwan Raza ◽  
Muhammad Ashraf Chaudhry ◽  
Bin Zhu
Keyword(s):  
Electron Microscopy ◽  
Fossil Fuels ◽  
Electrochemical Impedance ◽  
Renewable Energy Sources ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Doped Ceria ◽  
Alternative Source ◽  
Calcium Doped ◽  
Co Precipitation

The entire world’s challenge is to find out the renewable energy sources due to rapid depletion of fossil fuels because of their high consumption. Solid Oxide Fuel Cells (SOFCs) are believed to be the best alternative source which converts chemical energy into electricity without combustion. Nanostructured study is required to develop highly ionic conductive electrolyte for SOFCs. In this work, the calcium doped ceria (Ce0.8Ca0.2O1.9) coated with 20% molar ratio of two alkali carbonates (CDC-M: MCO3, where M = Na and K) electrolyte was prepared by co-precipitation method in this study. Ni based electrode was used to fabricate the cell by dry pressing technique. The crystal structure and surface morphology was characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). The particle size was calculated in the range of 10–20nm by Scherrer’s formula and compared with SEM and TEM results. The ionic conductivity was measured by using AC Electrochemical Impedance Spectroscopy (EIS) method. The activation energy was also evaluated. The performance of the cell was measured 0.567W/cm2 at temperature 550°C with hydrogen as a fuel.

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.

Investigation on Synthesis Conditions of Silicon-Doped Hydrotalcite-Like Compounds

2013 ◽  
Vol 781-784 ◽  
pp. 239-242
Author(s):  
Lei Wang ◽  
Peng Xiao
Keyword(s):  
Silicon Content ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Accurate Data ◽  
Aged Condition ◽  
Synthesis Conditions ◽  
Silicon Doped ◽  
Major Factors ◽  
Co Precipitation ◽  
Research Analysis

In this paper, SiMgAl hydotalcite synthesis conditions were investigated using co-precipitation method, within a relatively stable pH environment of 8~9. Our research, analysis and discussion focused on the effects of major factors, such as material molar ratio ,silicon content and aged condition, on the structures of synthetic products. To achieve stable and accurate data, synthetic products were characterized by XRD and IR under the identical conditions. As shown in the results, it is suggested that the best Crystallization temperature is 70°C, molar ratio of Mg to Al is 3:1, and the best content of Silicon is 0.015mol/mol.

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