scholarly journals CO2 hydrogenation to dimethyl ether over In2O3 catalysts supported on aluminosilicate halloysite nanotubes

2021 ◽  
Vol 10 (1) ◽  
pp. 594-605
Author(s):  
Alexey Pechenkin ◽  
Dmitry Potemkin ◽  
Sukhe Badmaev ◽  
Ekaterina Smirnova ◽  
Kirill Cherednichenko ◽  
...  
Keyword(s):  
Dimethyl Ether ◽  
Catalytic Properties ◽  
Fixed Bed ◽  
Nitrogen Adsorption ◽  
Halloysite Nanotubes ◽  
Molar Ratio ◽  
Stable Operation ◽  
Bifunctional Catalysts ◽  
Stainless Steel Reactor ◽  
Mcm 41

Abstract This work presents results on CO2 hydrogenation to dimethyl ether (DME) over bifunctional catalysts consisting of In2O3, supported on natural clay halloysite nanotubes (HNT), and HNT modified with Al-MCM-41 silica arrays. The catalysts were characterized by TEM, STEM, EDX-mapping, NH3-TPD, XRD, low-temperature nitrogen adsorption, TPO, and H2-TPR techniques. Catalytic properties of In2O3/HNT and In2O3/Al-MCM-41/HNT in the CO2 hydrogenation to DME were investigated in a fixed-bed continuous flow stainless steel reactor at 10–40 atm, in the temperature range of 200–300°C, at GHSV = 12,000 h−1 and molar ratio of H2:CO2 = 3:1. The best catalyst for CO2 hydrogenation was In2O3/Al-MCM-41/HNT that provided DME production rate 0.15 gDME·(gcat·h)−1 with DME selectivity 53% and at 40 bar, GHSV = 12,000 h−1, and T = 250°C. It was shown that In2O3/Al-MCM-41/HNT exhibited stable operation for at least 40 h on stream.

scholarly journals Ruthenium Catalysts Templated on Mesoporous MCM-41 Type Silica and Natural Clay Nanotubes for Hydrogenation of Benzene to Cyclohexane

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 537 ◽  
Author(s):  
Aleksandr Glotov ◽  
Anna Vutolkina ◽  
Aleksey Pimerzin ◽  
Vladimir Nedolivko ◽  
Gleb Zasypalov ◽  
...  
Keyword(s):  
Specific Activity ◽  
Nitrogen Adsorption ◽  
Halloysite Nanotubes ◽  
High Specific Surface Area ◽  
Ruthenium Catalysts ◽  
Molar Ratio ◽  
Benzene Hydrogenation ◽  
Ru Nanoparticles ◽  
Clay Nanotubes ◽  
Mcm 41

Mesoporous ruthenium catalysts (0.74–3.06 wt%) based on ordered Mobil Composition of Matter No. 41 (MCM-41) silica arrays on aluminosilicate halloysite nanotubes (HNTs), as well as HNT-based counterparts, were synthesized and tested in benzene hydrogenation. The structure of HNT core-shell silica composite-supported Ru catalysts were investigated by transmission electron microscopy (TEM), X-ray fluorescence (XRF) and temperature-programmed reduction (TPR-H2). The textural characteristics were specified by low-temperature nitrogen adsorption/desorption. The catalytic evaluation of Ru nanoparticles supported on both the pristine HNTs and MCM-41/HNT composite in benzene hydrogenation was carried out in a Parr multiple reactor system with batch stirred reactors (autoclaves) at 80 °C, a hydrogen pressure of 3.0 MPa and a hydrogen/benzene molar ratio of 3.3. Due to its hierarchical structure and high specific surface area, the MCM-41/HNT composite provided the uniform distribution and stabilization of Ru nanoparticles (NPs) resulted in the higher specific activity and stability as compared with the HNT-based counterpart. The highest specific activity (5594 h−1) along with deep benzene hydrogenation to cyclohexane was achieved for the Ru/MCM-41/HNT catalyst with a low metal content.

Effect of CeO2 Promoter on Catalytic Performance of CuO-ZnO-ZrO2/HZSM-5 Catalyst for Carbon Dioxide Hydrogenation into Dimethyl Ether

2012 ◽  
Vol 535-537 ◽  
pp. 2139-2142
Author(s):  
Ming Yu Zhang ◽  
Hua Wang ◽  
Wen Gui Gao
Keyword(s):  
Carbon Dioxide ◽  
Dimethyl Ether ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Bifunctional Catalysts ◽  
Dme Synthesis ◽  
Carbon Dioxide Hydrogenation

A series of CuO-ZnO-CeO2-ZrO2/HZSM-5 catalysts were prepared and characterized by XRD, H2-TPR. CO2hydrogenation to DME was carried out in a fixed bed reactor to test the catalytic performance of Ce-modified CuO-ZnO-ZrO2/HZSM-5 catalyst under the condition of GHSV=1800 h-1, p=3.0 MPa and T=250°C. The results indicate that the added CeO2improved the performance of the bifunctional catalysts, the CO2conversion and DME selectivity were obviously improved. CuO-ZnO-CeO2-ZrO2/HZSM-5 catalyst with Ce to Zr molar ratio of 1/1 showed the highest activity for DME synthesis from CO2hydrogenation.

Synthesis of Nanoporous Materials Al-MCM-41 from Natural Halloysite

NANO ◽  
2015 ◽  
Vol 10 (01) ◽  
pp. 1550005 ◽  
Author(s):  
Yaling Xie ◽  
Aidong Tang ◽  
Huaming Yang
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Halloysite Nanotubes ◽  
Nanoporous Materials ◽  
Molar Ratio ◽  
Molar Ratios ◽  
Naoh Solution ◽  
The One ◽  
Mcm 41

Nanoporous materials Al -MCM-41 with varying Si / Al molar ratios have been successfully synthesized from natural clay mineral halloysite nanotubes (HNTs). Hydrothermal treatment of acid-pretreated HNTs and NaOH solution resulted in the one-step synthesis of final nanoporous products by using surfactant. The effects of Si / Al molar ratios (7.7, 61.0 and 176.5) on the surface area, porosity and degree of structural order of Al -MCM-41 materials have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption–desorption measurements and Fourier transform infrared (FTIR) spectra techniques. The results indicated that Si / Al molar ratio had important effect on the characteristics of nanoporous materials, and Al -MCM-41 with an intermediate Si / Al molar ratio of 61.0 exhibited excellent characteristics with high degree of order, high surface area (S BET ) of 1033 m2/g and pore volume of 0.92 mL/g.

scholarly journals Ex-LDH-Based Catalysts for CO2 Conversion to Methanol and Dimethyl Ether

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 615
Author(s):  
Mauro Mureddu ◽  
Sarah Lai ◽  
Luciano Atzori ◽  
Elisabetta Rombi ◽  
Francesca Ferrara ◽  
...  
Keyword(s):  
Dimethyl Ether ◽  
Surface Acidity ◽  
Molar Ratio ◽  
Bifunctional Catalysts ◽  
Co2 Conversion ◽  
Experimental Conditions ◽  
Hydrogenation Catalysts ◽  
Methanol Production ◽  
Bulk Chemicals ◽  
Renewable Hydrogen

CO2-derived methanol and dimethyl ether can play a very important role as fuels, energy carriers, and bulk chemicals. Methanol production from CO2 and renewable hydrogen is considered to be one of the most promising pathways to alleviate global warming. In turn, methanol could be subsequently dehydrated into DME; alternatively, one-step CO2 conversion to DME can be obtained by hydrogenation on bifunctional catalysts. In this light, four oxide catalysts with the same Cu and Zn content (Cu/Zn molar ratio = 2) were synthesized by calcining the corresponding CuZnAl LDH systems modified with Zr and/or Ce. The fresh ex-LDH catalysts were characterized in terms of composition, texture, structure, surface acidity and basicity, and reducibility. Structural and acid–base properties were also studied on H2-treated samples, on which specific metal surface area and dispersion of metallic Cu were determined as well. After in situ H2 treatment, the ex-LDH systems were tested as catalysts for the hydrogenation of CO2 to methanol at 250 °C and 3.0 MPa. In the same experimental conditions, CO2 conversion into dimethyl ether was studied on bifunctional catalysts obtained by physically mixing the exLDH hydrogenation catalysts with acid ferrierite or ZSM-5 zeolites. For both processes, the effect of the Al/Zr/Ce ratio on the products distribution was investigated.

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.

CO2 valorization into synthetic natural gas (SNG) using a Co–Ni bimetallic Y2O3 based catalysts

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Radwa A. El-Salamony ◽  
Sara A. El-Sharaky ◽  
Seham A. Al-Temtamy ◽  
Ahmed M. Al-Sabagh ◽  
Hamada M. Killa
Keyword(s):  
Reaction Mechanism ◽  
Natural Gas ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Impregnation Method ◽  
Synthetic Natural Gas ◽  
Methanation Reaction ◽  
Co2 Valorization

Abstract Recently, because of the increasing demand for natural gas and the reduction of greenhouse gases, interests have focused on producing synthetic natural gas (SNG), which is suggested as an important future energy carrier. Hydrogenation of CO2, the so-called methanation reaction, is a suitable technique for the fixation of CO2. Nickel supported on yttrium oxide and promoted with cobalt were prepared by the wet-impregnation method respectively and characterized using SBET, XRD, FTIR, XPS, TPR, and HRTEM/EDX. CO2 hydrogenation over the Ni/Y2O3 catalyst was examined and compared with Co–Ni/Y2O3 catalysts, Co% = 10 and 15 wt/wt. The catalytic test was conducted with the use of a fixed-bed reactor under atmospheric pressure. The catalytic performance temperature was 350 °C with a supply of H2:CO2 molar ratio of 4 and a total flow rate of 200 mL/min. The CH4 yield was reached 67%, and CO2 conversion extended 48.5% with CO traces over 10Co–Ni/Y2O3 catalyst. This encourages the direct methanation reaction mechanism. However, the reaction mechanism over Ni/Y2O3 catalyst shows different behaviors rather than that over bi-metal catalysts, whereas the steam reforming of methane reaction was arisen associated with methane consumption besides increase in H2 and CO formation; at the same temperature reaction.

scholarly journals Grafting of (3-Chloropropyl)-Trimethoxy Silane on Halloysite Nanotubes Surface

2021 ◽  
Vol 11 (12) ◽  
pp. 5534
Author(s):  
Asmaa M. Abu El-Soad ◽  
Giuseppe Lazzara ◽  
Alexander V. Pestov ◽  
Daria P. Tambasova ◽  
Denis O. Antonov ◽  
...  
Keyword(s):  
Active Site ◽  
Chemical Engineering ◽  
Coupling Reaction ◽  
Ammonium Hydroxide ◽  
Halloysite Nanotubes ◽  
Chemical Activity ◽  
Molar Ratio ◽  
New Materials ◽  
Experimental Conditions ◽  
Trimethoxy Silane

Modified halloysite nanotubes (HNTs-Cl) were synthesized by a coupling reaction with (3-chloropropyl) trimethoxysilane (CPTMS). The incorporation of chloro-silane onto HNTs surface creates HNTs-Cl, which has great chemical activity and is considered a good candidate as an active site that reacts with other active molecules in order to create new materials with great applications in chemical engineering and nanotechnology. The value of this work lies in the fact that improving the degree of grafting of chloro-silane onto the HNT’s surface has been accomplished by incorporation of HNTs with CPTMS under different experimental conditions. Many parameters, such as the dispersing media, the molar ratio of HNTs/CPTMS/H2O, refluxing time, and the type of catalyst were studied. The greatest degree of grafting was accomplished by using toluene as a medium for the grafting process, with a molar ratio of HNTs/CPTMS/H2O of 1:1:3, and a refluxing time of 4 h. The addition of 7.169 mmol of triethylamine (Et3N) and 25.97 mmol of ammonium hydroxide (NH4OH) led to an increase in the degree of grafting of CPTMS onto the HNT’s surface.

Synthesis and Characterization of Different γ-Al2O3 Nanocatalysts for Methanol Dehydration to Dimethyl Ether

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Seyyed Ya'ghoob Hosseini ◽  
Mohammad Reza Khosravi Nikou
Keyword(s):  
Dimethyl Ether ◽  
Solid Acid Catalyst ◽  
Fixed Bed ◽  
Operating Parameter ◽  
Textural Properties ◽  
Ammonia Solution ◽  
Precipitation Method ◽  
High Yield ◽  
Methanol Dehydration ◽  
Adsorption Desorption

Abstract A simple co-precipitation method was utilized to synthesize γ-Al2O3 catalysts using aluminum nitrate nonahydrate as the source of aluminum cations for methanol dehydration to dimethyl ether (DME). Different precipitating agents comprising ammonium carbonate, ammonium bicarbonate and ammonia solutions were used for preparation of the samples. The catalysts were characterized by XRD, FTIR, SEM, NH3-TPD and N2 adsorption-desorption techniques. The sample prepared by ammonia solution had the highest acidity among the synthesized catalysts. Also, N2 adsorption-desorption results showed suitable textural properties for all of the synthesized samples. Vapor phase dehydration of methanol to DME was performed in the fixed bed micro reactor over the synthesized catalysts and commercial one for comparison purposes. The effects of different characteristics of catalysts such as surface area, acidity, sintering factor and temperature as an operating parameter on performance of catalysts were investigated. The catalyst prepared by ammonia solution showed best catalytic activity due to the suitable textural properties and high amount of acidic sites. Also, the results showed that only high acid strength can’t result high yield of DME for a solid acid catalyst.

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