scholarly journals Revisiting Oxidative Dehydrogenation of Ethane by W Doping into MoVMn Mixed Oxides at Low Temperature

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Mohammed H. Al-Hazmi ◽  
Taiwo Odedairo ◽  
Adel S. Al-Dossari ◽  
YongMan Choi
Keyword(s):  
Oxidative Dehydrogenation ◽  
Oxide Catalyst ◽  
Mixed Oxides ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxidative Dehydrogenation Of Ethane ◽  
Mixed Oxide Catalyst ◽  
Ethylene Selectivity ◽  
Temperature Programmed

The catalytic performance of MoVMnW mixed oxides was investigated in the oxidative dehydrogenation of ethane at three different reaction temperatures (235, 255, and 275°C) using oxygen as an oxidant. The catalysts were characterized by using X-ray diffraction, temperature-programmed reduction, and scanning electron microscopy. The MoVMnW mixed oxide catalyst showed the 70–90% of ethylene selectivity at the reaction temperatures. However, a significant decrease in the selectivity of ethylene was observed by increasing the reaction temperature from 235°C to 275°C.

Oxidation of thiophene over copper-manganese mixed oxides

2009 ◽  
Vol 63 (2) ◽  
Author(s):  
Małgorzata Szynkowska ◽  
Aneta Węglińska ◽  
Elżbieta Wojciechowska ◽  
Tadeusz Paryjczak
Keyword(s):  
Noble Metals ◽  
Mixed Oxides ◽  
Diffraction Method ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Copper Manganese ◽  
Different Temperatures ◽  
Temperature Programmed ◽  
Lower Temperature

AbstractCommercial hopcalite calcined at different temperatures and hopcalite modified with noble metals (Pt, Pd, and Au) were studied in oxidation of thiophene. Surface and bulk properties of catalysts were studied using temperature-programmed reduction (TPRH2), X-ray diffraction method (XRD) and thermal analysis (TG-DTA-MS). It was shown that calcined samples displayed higher activity in comparison with commercial untreated hopcalite; however, a lower temperature of calcination was favourable. High temperature of thermal treatment induced an increase in the crystallinity and a decrease in the surface area of the samples, and, as a consequence, the loss of catalysts activity. Moreover, marked improvement in the catalytic performance of platinum and palladium modified catalysts in relation to base hopcalite was observed. The obtained results indicate that the higher activity of samples containing Pt and Pd was accompanied by better reducibility of the catalysts.

scholarly journals Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1771 ◽  
Author(s):  
Stefan Neatu ◽  
Mihaela M. Trandafir ◽  
Adelina Stănoiu ◽  
Ovidiu G. Florea ◽  
Cristian E. Simion ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Catalytic Combustion Of Methane ◽  
Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

Oxidative dehydrogenation of ethane over a Mo–V–Nb–Te–O mixed-oxide catalyst in a cyclic mode

2017 ◽  
Vol 58 (2) ◽  
pp. 156-160 ◽  
Author(s):  
I. I. Mishanin ◽  
A. N. Kalenchuk ◽  
K. I. Maslakov ◽  
V. V. Lunin ◽  
A. E. Koklin ◽  
...  
Keyword(s):  
Oxidative Dehydrogenation ◽  
Mixed Oxide ◽  
Oxide Catalyst ◽  
Cyclic Mode ◽  
Oxidative Dehydrogenation Of Ethane ◽  
Mixed Oxide Catalyst

scholarly journals Generalized Methodology for Inserting Metal Heteroatoms into the Layered Zeolite Precursor RUB-36 by Interlayer Expansion

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 530 ◽  
Author(s):  
Chaoqun Bian ◽  
Xiao Wang ◽  
Lan Yu ◽  
Fen Zhang ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
Zeolite Sample ◽  
X Ray ◽  
Inductively Coupled ◽  
Temperature Programmed ◽  
First Time ◽  
N2 Sorption

The incorporation of metal heteroatoms into zeolites is an effective modification strategy for enhancing their catalytic performance. Herein, for the first time we report a generalized methodology for inserting metal heteroatoms (such as Sn, Fe, Zn, and Co) into the layered zeolite precursor RUB-36 via interlayer expansion by using the corresponding metal acetylacetate salt. Through this generalized methodology, Sn-JHP-1, Fe-JHP-1, Zn-JHP-1 and Co-JHP-1 zeolites could be successfully prepared by the reaction of RUB-36 and corresponding metal acetylacetate salt at 180 °C for 24 h in the presence of HCl solution. As a typical example, Sn-JHP-1 and calcined Sn-JHP-1 (Sn-JHP-2) zeolite is well characterized by the X-ray diffraction (XRD), diffuse reflectance ultraviolet-visible (UV-Vis), inductively coupled plasma (ICP), N2 sorption, temperature-programmed-desorption of ammonia (NH3-TPD) and X-ray photoelectron spectroscopy (XPS) techniques, which confirm the expansion of adjacent interlayers and thus the incorporation of isolated Sn sites within the zeolite structure. Notably, the obtained Sn-JHP-2 zeolite sample shows enhanced catalytic performance in the conversion of glucose to levulinic acid (LA) reaction.

scholarly journals Kinetic Study of Oxidative Dehydrogenation of Ethane over MoVTeNb Mixed-Oxide Catalyst

2013 ◽  
Vol 53 (5) ◽  
pp. 1775-1786 ◽  
Author(s):  
Jaime S. Valente ◽  
R. Quintana-Solórzano ◽  
H. Armendáriz-Herrera ◽  
G. Barragán-Rodríguez ◽  
J. M. López-Nieto
Keyword(s):  
Kinetic Study ◽  
Oxidative Dehydrogenation ◽  
Mixed Oxide ◽  
Oxide Catalyst ◽  
Oxidative Dehydrogenation Of Ethane ◽  
Mixed Oxide Catalyst

Dynamic and Steady State Analysis of Low Temperature Ethane Oxidative Dehydrogenation over Chromia and Chromia-Vanadia Catalysts

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Gulsun Karamullaoglu ◽  
Timur Dogu
Keyword(s):  
Gas Phase ◽  
Oxidative Dehydrogenation ◽  
Mixed Oxide ◽  
Oxide Catalyst ◽  
Feed Ratio ◽  
Mixed Oxide Catalysts ◽  
Mixed Oxide Catalyst ◽  
Dynamic Experiments ◽  
Ethane Oxidative Dehydrogenation ◽  
Ethylene Selectivity

Oxidative dehydrogenation of ethane to ethylene was investigated over Chromia and Cr-V mixed oxide catalysts synthesized following a complexation procedure. With an O2/C2H6 feed ratio of 0.17, Chromia exhibited a total conversion value of about 0.20 at 447°C (at a space time of 0.24 s.g/mL) with an ethylene selectivity of 0.82. Chromia catalyst was more active than Cr-V mixed oxide at temperatures as low as 200°C. Pulse-response experiments carried out with ethane pulses injected into O2-He indicated the presence of at least two different sites for the formation of CO2 and H2O over Chromia catalyst. In the dynamic experiments carried out with the Cr-V mixed oxide catalyst and by injecting O2 pulses into a gas stream containing a mixture of C2H6 and He, formation of CO rather than C2H4 was favored. Results of the dynamic runs carried out without gas phase oxygen strengthened the conclusion of lattice oxygen participation in the selective oxidation of ethane reaction through a redox mechanism.

Catalytic Activity of Bimetallic Cu-Ag/MgO-SiO2 Toward the Conversion of Ethanol to 1,3-Butadiene

2016 ◽  
Vol 14 (5) ◽  
pp. 945-954 ◽  
Author(s):  
Anamol Tripathi ◽  
Kajornsak Faungnawakij ◽  
Apirat Laobuthee ◽  
Suttichai Assabumrungrat ◽  
Navadol Laosiripojna
Keyword(s):  
Chemical Properties ◽  
Catalytic Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Monometallic Catalysts ◽  
Reaction Test ◽  
Spent Catalysts ◽  
Temperature Programmed ◽  
Preparation Techniques ◽  
Microwave Assisted Method

Abstract In the present work, the catalytic conversion of ethanol to 1,3-butadiene (1,3-BD) was studied over monometallic of Cu and Ag, and bimetallic Cu-Ag supported on MgO-SiO2 (with MgO/SiO2 ratio of 2.0) under the temperature range from 250 to 325 °C. All catalysts were prepared by 4 different techniques including (i) conventional impregnation, (ii) microwave-assisted method, (iii) polyvinyl alcohol/sodium borohydride (PVA/NaBH4) assisted method, and (iv) benzoxaxine-assisted method to elucidate the effect of catalyst preparation method on their catalytic performance. All fresh and spent catalysts were also characterized by X-ray diffraction (XRD), N2 adsorption and Temperature-programmed reduction (TPR) techniques to understand the relation between their physical/chemical properties and catalytic performance. From the reaction test, it was found that 5 %Ag/MgO-SiO2 showed greater activity towards 1,3-BD production than 5 %Cu/MgO-SiO2; nevertheless, higher deactivation after 6 h of operation was observed from 5 %Ag/MgO-SiO2. Importantly, this study revealed that bimetallic 2.5 %Cu-2.5 %Ag/MgO-SiO2 enhanced significantly higher activity and stability towards the reaction than monometallic catalysts. In addition, 2.5 %Cu-2.5 %Ag/MgO-SiO2 prepared by benzoxaxine-assisted method enhanced significantly higher reaction activity and stability than other preparation techniques, from which 1,3-BD yield of 46.40 % after 6 h of operation can be achieved. From the characterization, the good activity of this catalyst is mainly due to the dispersion improvement of metal over MgO-SiO2 support.

scholarly journals CuAlCe Oxides Issued from Layered Double Hydroxide Precursors for Ethanol and Toluene Total Oxidation

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 870
Author(s):  
Hadi Dib ◽  
Rebecca El Khawaja ◽  
Guillaume Rochard ◽  
Christophe Poupin ◽  
Stéphane Siffert ◽  
...  
Keyword(s):  
Layered Double Hydroxide ◽  
Mixed Oxides ◽  
Synergetic Effect ◽  
Catalytic Performance ◽  
Total Oxidation ◽  
X Ray ◽  
Volatile Organic ◽  
Temperature Programmed ◽  
Toluene Total Oxidation ◽  
Double Hydroxide

CuAlCe oxides were obtained from hydrotalcite-type precursors by coprecipitation using a M2+/M3+ ratio of 3. The collapse of the layered double hydroxide structure following the thermal treatment leads to the formation of mixed oxides (CuO and CeO2). The catalytic performance of the copper-based catalysts was evaluated in the total oxidation of two Volatile Organic Compounds (VOCs): ethanol and toluene. XRD, SEM Energy-Dispersive X-ray Spectrometry (EDX), H2-temperature programmed reduction (TPR) and XPS were used to characterize the physicochemical properties of the catalysts. A beneficial effect of combining cerium with CuAl-O oxides in terms of redox properties and the abatement of the mentioned VOCs was demonstrated. The sample with the highest content of Ce showed the best catalytic properties, which were mainly related to the improvement of the reducibility of the copper species and their good dispersion on the surface. The presence of a synergetic effect between the copper and cerium elements was also highlighted.

The Different Morphology of Co3O4 Catalysts and Application in the Abatement of Carbon Monoxide

2021 ◽  
Vol 21 (12) ◽  
pp. 6082-6087
Author(s):  
Chih-Wei Tang ◽  
Hsiang-Yu Shih ◽  
Ruei-Ci Wu ◽  
Chih-Chia Wang ◽  
Chen-Bin Wang
Keyword(s):  
Carbon Monoxide ◽  
Catalytic Activity ◽  
Co Oxidation ◽  
Nitrogen Adsorption ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Adsorption Desorption

The increase of harmful carbon monoxide (CO) caused by incomplete combustion can affect human health even lead to suffocation. Therefore reducing the CO discharged by vehicles or factories is urgent to improve the air quality. The spinel cobalt (II, III) oxide (Co3O4) is an active catalyst for CO abatement. In this study, we tried to fabricate dispersing Co3O4 via the dispersion-precipitation method with acetic acid, formic acid, and oxalic acid as the chelating dispersants. Then, the asprepared samples were calcined at 300 ºC for 4 h to obtain active catalysts, and assigned as Co(A), Co(F) and Co(O) respectively, the amount of the dispersants used are labeled as I (0.12 mole), II (0.03 mole) and III (0.01 mole). For comparison, another CoAP sample was prepared via alkaliinduced precipitation and calcined at 300 ºC. All samples were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), scanning electron microscope (SEM), and nitrogen adsorption/desorption system, and the catalytic activity focused on the CO oxidation. The influence of chelating dispersant on the performance of abatement of CO was pursued in this study. Apparently, the results showed that the chelating dispersant can influence the catalytic activity of CO abatement. An optimized ratio of dispersant can improve the performance, while excess dispersant lessens the surface area and catalytic performance. The series of Co(O) samples can easily donate the active oxygen since the labile Co–O bonding and indicated the preferential performance than both Co(A) and Co(F) samples. The nanorod Co(O)-II showed preferential for CO oxidation, T50 and T90 approached 96 and 127 ºC, respectively. Also, the favorable durability of Co(O)-II sample maintains 95% conversion still for 50 h at 130 ºC and does not emerge deactivation.

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