Preparation and Property of Y-Mg-Al-Layered Double Oxides

2011 ◽  
Vol 396-398 ◽  
pp. 764-767
Author(s):  
Tai Xuan Jia ◽  
Ji Chang Zhang ◽  
Zi Li Liu
Keyword(s):  
Condensation Reaction ◽  
Fixed Bed ◽  
Space Velocity ◽  
Precipitation Method ◽  
High Catalytic Activity ◽  
Liquid Hourly Space Velocity ◽  
Maximum Value ◽  
Co Precipitation ◽  
Micro Reactor ◽  
Acetone Condensation

Y-Mg-Al-layered double Oxides (Y-Mg-Al-LDO) were prepared by calcining Y3+-doped Mg-Al-layered hydrotalcites at 823 K for 8 h from co-precipitation method. The samples were detected by XRD and CO2-TPD. Micro-structure and essential regularity were disclosed. The acetone condensation reaction as a probe reaction was carried on fixed-bed micro-reactor at reactive temperature 673 K, reactive time 3 h and liquid hourly space velocity (LHSV) 6 h-1 over Y-Mg-Al-LDO. The catalyst evaluation results show that Y-Mg-Al-LDO possess high catalytic activity. The maximum value of acetone conversion reached 37.53%. The selectivity and single-pass-yield of isophorone were 55.66% and 20.89%, respectively.

Dimethyldisulphide Hydrodesulphurization on NiCoMo / Al2O3 Catalyst

2017 ◽  
Vol 68 (7) ◽  
pp. 1496-1500
Author(s):  
Rami Doukeh ◽  
Mihaela Bombos ◽  
Ancuta Trifoi ◽  
Minodora Pasare ◽  
Ionut Banu ◽  
...  
Keyword(s):  
Good Accuracy ◽  
Fixed Bed ◽  
Continuous System ◽  
Space Velocity ◽  
Molar Ratio ◽  
Catalytic Reactor ◽  
Liquid Hourly Space Velocity ◽  
Hydrodesulfurization Process ◽  
Al2o3 Catalyst ◽  
Simplified Kinetic Model

Hydrodesulphurization of dimethyldisulphide was performed on Ni-Co-Mo /�-Al2O3 catalyst. The catalyst was characterized by determining the adsorption isotherms, the pore size distribution and the acid strength. Experiments were carried out on a laboratory echipament in continuous system using a fixed bed catalytic reactor at 50-100�C, pressure from 10 barr to 50 barr, the liquid hourly space velocity from 1h-1 to 4h-1 and the molar ratio H2 / dimethyldisulphide 60/1. A simplified kinetic model based on the Langmuir�Hinshelwood theory, for the dimethyldisulphide hydrodesulfurization process of dimethyldisulphide has been proposed. The results show the good accuracy of the model.

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.

High Catalytic Activity and Stability of Hexaaluminate Catalysts for N2O Decomposition

2013 ◽  
Vol 320 ◽  
pp. 665-669
Author(s):  
Chao Zhang ◽  
Yong Ji Song ◽  
Feng Hua Shi ◽  
Cui Qing Li ◽  
Hong Wang
Keyword(s):  
Catalytic Activity ◽  
Decomposition Reaction ◽  
Precipitation Method ◽  
High Catalytic Activity ◽  
Structure And Properties ◽  
Active Components ◽  
Co Precipitation ◽  
Hexaaluminate Catalysts

In this paper, hexaaluminate oxides LaMAl12O19-σwere prepared by using M=Cu ,Ce and Zn as active components to substitute Al in the hexaaluminate lattice by co-precipitation method. The structure and properties of LaMAl11O19-σcatalyst was characterized with XRD and BET. The results showed LaCuAl11O19-σexhibited significant high catalytic activity for the decomposition reaction of N2O. Under the simulated in situ condition, LaCuAl11O19-σalso indicated significant catalytic activity and stability, with N2O conversion of 90% at 635°C.

Non-Thermal Plasma Assisted Catalytic Oxidation NO over Mn-Ni-Ox Catalysts at Low-Temperature

2011 ◽  
Vol 383-390 ◽  
pp. 3092-3098 ◽  
Author(s):  
Kai Li ◽  
Xiao Long Tang ◽  
Hong Hong Yi ◽  
Ping Ning ◽  
Zhi Qing Ye ◽  
...  
Keyword(s):  
Low Temperature ◽  
Catalytic Oxidation ◽  
Thermal Plasma ◽  
Space Velocity ◽  
Input Voltage ◽  
No Oxidation ◽  
Precipitation Method ◽  
Non Thermal Plasma ◽  
High Space ◽  
Co Precipitation

Mn-Ni-Ox catalyst was prepared by the co-precipitation method. The most active catalysts were obtained with a molar Ni/ (Mn+Ni) ratio of 0.1. The results showed that over this catalyst, NO oxidation conversion reached 59% at 125°C and 50% at 150°C with a high space velocity of 35000h-1. Their surface properties were evaluated by means of scanning electron microscopy (SEM). The process of non-thermal plasma-assisted catalytic oxidation of NO under low-temperature was studied. And the NO conversion could reach 80% with the non-thermal plasma-assisting at 150°C when the input voltage was 30V. The increasing activities at low temperature（50~175°C）were more apparently higher than high temperature by plasma. And the low-temperature catalytic activity of the catalyst was increased with the increase of the input voltage.

STUDY ON NANO COPPER-BASED CATALYSTS FOR THE HYDROGENATION OF METHYL 3-HYDROXYPROPIONATE TO 1, 3-PROPANEDIOL

2009 ◽  
Vol 16 (03) ◽  
pp. 343-349 ◽  
Author(s):  
YUZHOU YING ◽  
KANKA FENG ◽  
ZHIGUO LV ◽  
ZHENMEI GUO ◽  
JINSHENG GAO
Keyword(s):  
Fixed Bed ◽  
Side Reaction ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Precipitation Method ◽  
Active Components ◽  
Analysis Technique ◽  
Co Precipitation ◽  
Nano Catalysts ◽  
Adsorption Desorption

Nano copper-based catalysts were prepared by co-precipitation method and the performance of catalytic hydrogenation for methyl 3-hydroxypropionate (MHP) to 1, 3-propanediol (1, 3-PDO) on the nano catalysts were studied under a high-pressure microcontinuum fixed-bed reactor. The effects of structure, texture, and composition of the catalysts on the catalytic performance were investigated by characterizing the catalysts with XRD, TG–DTG, SEM, and N 2 adsorption/desorption analysis technique. The results showed that addition of promoters enhanced the activity and selectivity of copper-based catalysts, which promoted the dispersion of the active components effectively and stabilized the active center of the catalysts. Especially, the copper-based catalyst of loaded P could restrain side-reaction effectively and improve selectivity obviously, the conversion of MHP and the selectivity of 1, 3-PDO could be 91.30% and reach 90.15%, respectively.

scholarly journals The Influence of the Preparation Method on the Physico-Chemical Properties and Catalytic Activities of Ce-Modified LDH Structures Used as Catalysts in Condensation Reactions

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6191
Author(s):  
Alexandra-Elisabeta Stamate ◽  
Rodica Zăvoianu ◽  
Octavian Dumitru Pavel ◽  
Ruxandra Birjega ◽  
Andreea Matei ◽  
...  
Keyword(s):  
Preparation Method ◽  
Mixed Oxides ◽  
Condensation Reaction ◽  
Chemical Properties ◽  
Precipitation Method ◽  
Synthesis Methods ◽  
Molar Ratios ◽  
Base Catalysts ◽  
Physico Chemical ◽  
Co Precipitation

Mechanical activation and mechanochemical reactions are the subjects of mechanochemistry, a special branch of chemistry studied intensively since the 19th century. Herein, we comparably describe two synthesis methods used to obtain the following layered double hydroxide doped with cerium, Mg3Al0.75Ce0.25(OH)8(CO3)0.5·2H2O: the mechanochemical route and the co-precipitation method, respectively. The influence of the preparation method on the physico-chemical properties as determined by multiple techniques such as XRD, SEM, EDS, XPS, DRIFT, RAMAN, DR-UV-VIS, basicity, acidity, real/bulk densities, and BET measurements was also analyzed. The obtained samples, abbreviated HTCe-PP (prepared by co-precipitation) and HTCe-MC (prepared by mechanochemical method), and their corresponding mixed oxides, Ce-PP (resulting from HTCe-PP) and Ce-MC (resulting from HTCe-MC), were used as base catalysts in the self-condensation reaction of cyclohexanone and two Claisen–Schmidt condensations, which involve the reaction between an aromatic aldehyde and a ketone, at different molar ratios to synthesize compounds with significant biologic activity from the flavonoid family, namely chalcone (1,3-diphenyl-2-propen-1-one) and flavone (2-phenyl-4H-1benzoxiran-4-one). The mechanochemical route was shown to have indisputable advantages over the co-precipitation method for both the catalytic activity of the solids and the costs.

scholarly journals The Effects of Promoter Cs Loading on the Hydrogen Production from Ammonia Decomposition Using Ru/C Catalyst in a Fixed-Bed Reactor

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 321
Author(s):  
Yen-Ling Chen ◽  
Chin-Fang Juang ◽  
Yen-Cho Chen
Keyword(s):  
Hydrogen Production ◽  
Fixed Bed ◽  
Space Velocity ◽  
Ammonia Decomposition ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Carbon Catalyst ◽  
Molar Ratios ◽  
Maximum Value ◽  
Ammonia Conversion

The hydrogen production from ammonia decomposition on commercial 5 wt.% Ru/C (C: activated carbon) catalyst with different cesium (Cs) loadings at lower temperatures of 325–400 °C in the fixed-bed reactor was experimentally investigated. Based on the parameters used in this work, the results showed that the ammonia conversion at 350 °C is increased with the increasing Cs/Ru molar ratio, and it reaches its maximum value at the Cs/Ru molar ratio of 4.5. After that, it is rapidly decreased with a further increase of Cs/Ru molar ratio, and it is even smaller than that of the pure Ru/C case at the Cs/Ru molar ratio of 6. The Cs promotion at the lower Cs/Ru molar ratios may be due to the so-called “hot ring promotion”. The possible mechanisms for Cs effects on the ammonia conversion at higher Cs/Ru molar ratio are discussed. At optimum Cs loading, the results showed that all the ammonia conversions at 400 °C are near 100% for the GHSV (gas hourly space velocity) from 48,257 to 241,287 mL/(h·gcat).

scholarly journals PENGEMBANGAN PROSES UPGRADING MINYAK BATUBARA: Pengaruh Temperatur, Tekanan dan Space Velocity

2011 ◽  
Vol 7 (1) ◽  
pp. 26
Author(s):  
Yusnitati Yusnitati ◽  
Muhammad Hanif ◽  
M Faizal
Keyword(s):  
Fixed Bed ◽  
Space Velocity ◽  
Liquid Hourly Space Velocity

Minyak batubara cair dengan titik didih 70-360oC, diperoleh dari proses pencairan batubara Tanito Harum menggunakan NEDOL Process skala pilot berkapasitas 150 ton/hari. Minyak batubara cair tersebut diupgrade untuk mengklarifikasi pengaruh temperatur reaksi, tekanan hidrogen, dan liquid hourly space velocity (LHSV) terhadap aktifitas hidrodenitrogenasi. Pengujian dilakukan dalam reactor fixed bed kontinyu berdiameter 8.5 mm menggunakan katalis Ni- W/Alumina pada temperatur 300-375oC, tekanan hidrogen 8-12 MPa, LHSV 0.75-3.0 hr-1 dan rasio hydrogen/oil 1000 NL/L. Hasil pengujian menunjukkan bahwa aktifitas hidrodenitrogenasi meningkat dengan peningkatan temperature reaksi dan tekanan hidrogen. Pada tekanan hidrogen 8 MPa, deaktifasi katalis terjadi lebih cepat dibandingkan dengan tekanan hydrogen 12 MPa selama 15 hari waktu operasi. Selain itu, ditunjukkan pula bahwa pada operasi dengan LHSV yang lebih rendah dan tekanan hidrogen yang lebih tinggi akan lebih efektif untuk menurunkan atau menghilangkan senyawa nitrogen dalam proses upgrading minyak batubara cair. Sehingga, operasi pada tekanan hidrogen 12 MPa diharapkan dapat menghasilkan produk minyak batubara cair dengan kandungan nitrogen yang rendah untuk waktu operasi lebih dari satu tahun pada skala komersial. Kata Kunci: hidrodenitrogenasi, katalis Ni-W/Alumina, minyak batubara cair, upgrading

Synthesis of nanosphere-like LiCoPO4 with excellent electrochemical performance via micro reactor assisted co-precipitation method

2018 ◽  
Vol 11 (05) ◽  
pp. 1850037 ◽  
Author(s):  
Huifang Zhao ◽  
Yong Yu ◽  
Guojing Wang ◽  
Yunchao Chen ◽  
Xiaomin Liu ◽  
...  
Keyword(s):  
Carbon Coating ◽  
High Rate ◽  
Precipitation Method ◽  
Rate Performance ◽  
Initial Discharge Capacity ◽  
Initial Discharge ◽  
Excellent Electrochemical Performance ◽  
Co Precipitation ◽  
High Rate Performance ◽  
Micro Reactor

Li3PO4 and Co3(PO[Formula: see text]8H2O precursors, precipitated within a micro reactor using ethyl alcohol as anti-solvent, are sintered to form nanosphere-like LiCoPO4. Even without carbon coating, the resulting sample with 2.1[Formula: see text]wt.% Li3PO4 existence presents surprisingly high initial discharge capacity (up to 164[Formula: see text]mAh/g and 787[Formula: see text]Wh/kg at 0.1C) and superior high rate performance (117[Formula: see text]mAh/g and 561[Formula: see text]Wh/kg at 5C).

The Enhanced Saturation Magnetization of Nanocrystalline (Ni0.5Zn0.5)1-xCoxFe2O4 Ferrite

2011 ◽  
Vol 415-417 ◽  
pp. 1372-1375
Author(s):  
Yi Bing Qiu ◽  
Yin Liu ◽  
Fan Fei Min ◽  
Yan Cao ◽  
Tai Qiu ◽  
...  
Keyword(s):  
Saturation Magnetization ◽  
Magnetic Moment ◽  
Spinel Phase ◽  
Precipitation Method ◽  
Maximum Value ◽  
Nanocrystalline Ferrite ◽  
Co Precipitation

Single spinel phase nanocrystalline ferrite (Ni0.5Zn0.5)1-XCoxFe2O4was prepared using the spraying co-precipitation method. The coercivity of prepared (Ni0.5Zn0.5)1-XCoxFe2O4 increases with an increasing content of cobalt. The enhancement of the saturation magnetization was observed up to the maximum value of 102.1emu/g as x was 0.5. This can be attributed to the substitution of the Ni2+ and Zn2+ ions with Co2+ ions. This changed the net magnetic moment between the sublattices of structure.

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