scholarly journals Conversion of bioethanol over oxide catalysts

2019 ◽  
Vol 17 (1) ◽  
pp. 40-46
Author(s):  
G. Y. Yergaziyeva ◽  
S. Tayrabekova ◽  
M. Mambetova ◽  
S. Ozganbayeva ◽  
S. Smagulova
Keyword(s):  
Copper Catalyst ◽  
Space Velocity ◽  
Acid Sites ◽  
Oxide Catalysts ◽  
Hydrogen Yield ◽  
Production Of Hydrogen ◽  
Adsorption Desorption ◽  
Positive Effect ◽  
Al2o3 Catalyst ◽  
Modification Of Catalysts

The conversion of bioethanol over supported oxide catalysts (CuO, ZnO, Cr2O3,CeO2) was studied, among which the most active in the production of hydrogenis 3% CuO / γ-Al2O3. Modification of 3% CuO / γ-Al2O3 catalyst with Cr2O3, ZnOand CeO2 promotes the growth of hydrogen yield. The highest concentrationof hydrogen at 300° C and a space velocity of 1 h-1 on CuO-ZnO / γ-Al2O3 was48% by volume. The acidity of catalysts for adsorption-desorption of pyridine byinfrared spectroscopy (ITI Matson FTIR) was determined. When the content ofCuO in the catalyst is increased from 1 to 3%, the amount of Lewis acidic centers(LAS) increases from 58 to 82 µmol/ gcat. Modification with chromium oxide ofthe copper catalyst increases the number of LAS from 82 to 156 µmol/ gcat byadsorption of pyridine at 150° C and from 79 to 120 µmol/ gcat with pyridineadsorption at 250° C. It has been established that an increase in the number ofLewis acid sites has a positive effect on the yield of hydrogen in the conversion ofbioethanol. According to electron microscopy, the modification of catalysts leadsto an increase in the dispersity of the catalyst and to a uniform distribution ofparticles on the surface of the catalyst, which also contributes to its greater activityin the production of hydrogen.

scholarly journals Production of Hydrogen-Rich Gas by Oxidative Steam Reforming of Dimethoxymethane over CuO-CeO2/γ-Al2O3 Catalyst

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3684
Author(s):  
Sukhe Badmaev ◽  
Vladimir Sobyanin
Keyword(s):  
Fuel Cell ◽  
Partial Oxidation ◽  
Steam Reforming ◽  
Comparative Studies ◽  
Catalytic Properties ◽  
Fixed Bed ◽  
Space Velocity ◽  
Fixed Bed Reactor ◽  
Production Of Hydrogen ◽  
Al2o3 Catalyst

The catalytic properties of CuO-CeO2 supported on alumina for the oxidative steam reforming (OSR) of dimethoxymethane (DMM) to hydrogen-rich gas in a tubular fixed bed reactor were studied. The CuO-CeO2/γ-Al2O3 catalyst provided complete DMM conversion and hydrogen productivity > 10 L h−1 gcat−1 at 280 °C, GHSV (gas hourly space velocity) = 15,000 h−1 and DMM:O2:H2O:N2 = 10:2.5:40:47.5 vol.%. Comparative studies showed that DMM OSR exceeded DMM steam reforming (SR) and DMM partial oxidation (PO) in terms of hydrogen productivity. Thus, the outcomes of lab-scale catalytic experiments show high promise of DMM oxidative steam reforming to produce hydrogen-rich gas for fuel cell feeding.

scholarly journals Performance of a Ni-Cu-Co/Al2O3 Catalyst on in-situ Hydrodeoxygenation of Bio-derived Phenol

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 952 ◽  
Author(s):  
Huiyuan Xue ◽  
Xingxing Gong ◽  
Jingjing Xu ◽  
Rongrong Hu
Keyword(s):  
Electron Microscope ◽  
Synergistic Effects ◽  
X Ray ◽  
Transmission Electron ◽  
Production Of Hydrogen ◽  
Good Potential ◽  
Temperature Programmed ◽  
Positive Effect ◽  
Al2o3 Catalyst

The in-situ hydrodeoxygenation of bio-derived phenol is an attractive routine for upgrading bio-oils. Herein, an active trimetallic Ni-Cu-Co/Al2O3 catalyst was prepared and applied in the in-situ hydrodeoxygenation of bio-derived phenol. Comparison with the monometallic Ni/Al2O3 catalyst and the bimetallic Ni-Co/Al2O3 and Ni-Cu/Al2O3 catalysts, the Ni-Cu-Co/Al2O3 catalyst exhibited the highest catalytic activity because of the formation of Ni-Cu-Co alloy on the catalyst characterized by using X-ray powder diffraction (XRD), temperature programmed reduction (TPR), N2 physisorption, scanning electron microscope (SEM), and transmission electron microscope (TEM). The phenol conversion of 100% and the cyclohexane yield of 98.3% could be achieved in the in-situ hydrodeoxygenation of phenol at 240 °C and 4 MPa N2 for 6 h. The synergistic effects of Ni with Cu and Co of the trimetallic Ni-Cu-Co/Al2O3 catalyst played a significant role in the in-situ hydrodeoxygenation process of phenol, which not only had a positive effect on the production of hydrogen but also owned an excellent hydrogenolysis activity to accelerate the conversion of cyclohexanol to cyclohexane. Furthermore, the catalyst also exhibited excellent recyclability and good potential for the upgrading of bio-oils.

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.

scholarly journals Insight into Active Centers and Anti-Coke Behavior of Niobium-Containing SBA-15 for Glycerol Dehydration

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 488
Author(s):  
Katarzyna Stawicka ◽  
Maciej Trejda ◽  
Maria Ziolek
Keyword(s):  
Coke Formation ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Silica Matrix ◽  
High Concentration ◽  
Active Centers ◽  
Acidic Sites ◽  
Glycerol Dehydration ◽  
Adsorption Desorption ◽  
Insight Into

Niobium containing SBA-15 was prepared by two methods: impregnation with different amounts of ammonium niobate(V) oxalate (Nb-15/SBA-15 and Nb-25/SBA-15 containing 15 wt.% and 25 wt.% of Nb, respectively) and mixing of mesoporous silica with Nb2O5 followed by heating at 500 °C (Nb2O5/SBA-15). The use of these two procedures allowed obtaining materials with different textural/surface properties determined by N2 adsorption/desorption isotherms, XRD, UV-Vis, pyridine, and NO adsorption combined with FTIR spectroscopy. Nb2O5/SBA-15 contained exclusively crystalline Nb2O5 on the SBA-15 surface, whereas the materials prepared by impregnation had both metal oxide and niobium incorporated into the silica matrix. The niobium species localized in silica framework generated Brønsted (BAS) and Lewis (LAS) acid sites. The inclusion of niobium into SBA-15 skeleton was crucial for the achievement of high catalytic performance. The strongest BAS were on Nb-25/SBA-15, whereas the highest concentration of BAS and LAS was on Nb-15/SBA-15 surface. Nb2O5/SBA-15 material possessed only weak LAS and BAS. The presence of the strongest BAS (Nb-25/SBA-15) resulted in the highest dehydration activity, whereas a high concentration of BAS was unfavorable. Silylation of niobium catalysts prepared by impregnation reduced the number of acidic sites and significantly increased acrolein yield and selectivity (from ca. 43% selectivity for Nb-25/SBA-15 to ca. 61% for silylated sample). This was accompanied by a considerable decrease in coke formation (from 47% selectivity for Nb-25/SBA-15 to 27% for silylated material).

Ethylene polymerization on lewis acid sites of a reduced V2O5/Al2O3 catalyst

1992 ◽  
Vol 46 (1) ◽  
pp. 199-207 ◽  
Author(s):  
S. Ishida ◽  
S. Imamura ◽  
F. Ren ◽  
Y. Tatematsu ◽  
Y. Fujimura
Keyword(s):  
Lewis Acid ◽  
Ethylene Polymerization ◽  
Acid Sites ◽  
Lewis Acid Sites ◽  
Al2o3 Catalyst

scholarly journals Zinc Acetate Immobilized on Mesoporous Materials by Acetate Ionic Liquids as Catalysts for Vinyl Acetate Synthesis

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Hang Xu ◽  
Tianlong Yu ◽  
Mei Li
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Vinyl Acetate ◽  
Silica Gel ◽  
Catalyst Activity ◽  
Catalyst Layer ◽  
Space Velocity ◽  
Molar Ratio ◽  
Vinyl Acetate Monomer ◽  
Adsorption Desorption

Ionic liquid containing active ingredient Zn(CH3COO)2was loaded in mesoporous silica gel to form supported ionic liquids catalyst (SILC) which was used to synthesize vinyl acetate monomer (VAM). SILC was characterized by1HNMR, FT-IR, TGA, BET, and N2adsorption/desorption and the acetylene method was used to evaluate SILC catalytic activity and stability in fixed reactor. The result shows that 1-allyl-3-acetic ether imidazole acetate ionic liquid is successfully fixed within mesoporous channel of silica gel. The average thickness of ionic liquid catalyst layer is about 1.05 nm. When the catalytic temperature is 195°C, the acetic acid (HAc) conversion is 10.9% with 1.1 g vinyl acetate yield and 98% vinyl acetate (VAc) selectivity. The HAc conversion is increased by rise of catalytic temperature and molar ratio of C2H2 : HAc and decreased by mass space velocity (WHSV). The catalyst activity is not significantly reduced within 7 days and VAc selectivity has a slight decrease.

The Effect of Zinc Content on n-Pentane Isomerisation Over Zn–S2O82–/ZrO2–Al2O3 Catalyst

2017 ◽  
Vol 42 (1) ◽  
pp. 23-29
Author(s):  
Hua Song ◽  
Shengnan Li ◽  
Hualin Song ◽  
Feng Li ◽  
Huapeng Cui
Keyword(s):  
Zinc Content ◽  
Space Velocity ◽  
X Ray Diffraction ◽  
Sulfate Ions ◽  
X Ray ◽  
Weight Hourly Space Velocity ◽  
Mass Fractions ◽  
Crystallite Sizes ◽  
Temperature Programmed ◽  
Al2o3 Catalyst

A number of Zn–S2O82–/ZrO2–Al2O3 (Zn( x)–SZA) catalysts with different Zn mass fractions were synthesised and characterised by using X-ray diffraction, the Brunauer–Emmett–Teller method, and H2 temperature-programmed reduction. The structure and isomerisation performance of Zn( x)–SZA catalysts were studied using n-pentane as a probe reaction. The results showed that a pure tetragonal ZrO2 phase was formed on Zn( x)–SZA, and the ZrO2 crystallite sizes of the tetragonal phase increased in the order: Zn(0.5)–SZA < Zn(1.0)–SZA < Zn(1.5)–SZA < Zn(2.0)–SZA < SZA. Zn can strengthen the interaction between persulfate ions and the support, promote the formation of stronger acidity, lead to a better dispersion of sulfate ions on the surface, and improve the redox performance of the catalysts. The Zn(1.0)–SZA catalyst exhibited the best catalytic activity for n-pentane isomerisation. At a temperature of 170 °C, a reaction pressure of 2.0 MPa, a molar H2/ n-pentane ratio of 4:1, and a weight hourly space velocity of 1.0 h−1, the isopentane yield reached 58.0%.

In situ/operando studies for the production of hydrogen through the water-gas shift on metal oxide catalysts

2013 ◽  
Vol 15 (29) ◽  
pp. 12004 ◽  
Author(s):  
José A. Rodriguez ◽  
Jonathan C. Hanson ◽  
Dario Stacchiola ◽  
Sanjaya D. Senanayake
Keyword(s):  
Metal Oxide ◽  
Oxide Catalysts ◽  
Water Gas Shift ◽  
Metal Oxide Catalysts ◽  
Production Of Hydrogen ◽  
Water Gas ◽  
Operando Studies

Bio-electrochemical production of hydrogen and electricity from organic waste

2021 ◽  
Author(s):  
Giorgia De Gioannis ◽  
Alessandro Dell'Era ◽  
Aldo Muntoni ◽  
Mauro Pasquali ◽  
Alessandra Polettini ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Electron Flow ◽  
Dark Fermentation ◽  
Electrochemical Process ◽  
Integrated System ◽  
Galvanic Cell ◽  
Hydrogen Yield ◽  
Cell Coupling ◽  
Production Of Hydrogen ◽  
Acid Metabolites

Abstract This study investigated the performance of a novel integrated bio-electrochemical system for synergistic hydrogen production from a process combining a dark fermentation reactor and a galvanic cell. The operating principle of the system is based on the electrochemical conversion of protons released upon dissociation of the acid metabolites of the biological process and is mediated by the electron flow from the galvanic cell, coupling biochemical and electrochemical hydrogen production. Accordingly, the galvanic compartment also generates electricity. Four different experimental setups were designed to provide a preliminary assessment of the integrated bio-electrochemical process and identify the optimal configuration for further tests. Subsequently, dark fermentation of cheese whey was implemented both in a stand-alone biochemical reactor and in the integrated bio-electrochemical process. The integrated system achieved a hydrogen yield in the range 75.5 – 78.8 N LH2/kg TOC, showing a 3 times improvement over the biochemical process.

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