Comparative Studies of the CoMo/MgO, CoMo/Al2O3 and CoMo/MgO-MgAl2O4 Catalysts Prepared by a Urea-Matrix Combustion Method

2010 ◽  
Vol 132 ◽  
pp. 45-54 ◽  
Author(s):  
Li Bao Wu ◽  
Dong Mei Jiao ◽  
Li Fang Chen ◽  
Jin An Wang ◽  
Fa Hai Cao
Keyword(s):  
Supported Catalysts ◽  
Fixed Bed ◽  
Combustion Method ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Isothermal Adsorption ◽  
X Ray ◽  
Species Formation ◽  
Temperature Programmed ◽  
Adsorption Desorption

Three CoMo supported catalysts with different supports, Al2O3, MgO and MgO-MgAl2O4, were prepared by a urea matrix combustion method. The physicochemical properties of the catalysts were characterized by N2 isothermal adsorption–desorption, powder X-ray diffraction (XRD) and temperature programmed reduction (TPR) techniques. The activity of these catalysts was evaluated in a fixed-bed high-pressure reactor using hydrodesulfurization of dibenzothiophene as a model reaction. The urea matrix combustion preparation method greatly favored the formation of highly dispersed Co- and Mo-oxo species on the support, which had significant influence on the hydrodesulfurization (HDS) activity. XRD analysis showed that MgO was more sensitive to the deposition of Co-O or Mo-O species than Al2O3 and MgAl2O4; the former might be potentially used as an indicator of the Co- and Mo-oxo species formation. Among these catalysts, CoMo/MgO-MgAl2O4 exhibited a high HDS activity.

scholarly journals Catalytic oxidation of CO over CuO/CeO2 nanocomposites synthesized via solution combustion method: effect of fuels

2020 ◽  
Vol 59 (1) ◽  
pp. 131-143 ◽  
Author(s):  
Thanh Son Cam ◽  
Tatyana Alekseevna Vishnievskaia ◽  
Vadim Igorevich Popkov
Keyword(s):  
Low Temperature ◽  
Co Oxidation ◽  
Combustion Method ◽  
X Ray Diffraction ◽  
Solution Combustion ◽  
Solution Combustion Method ◽  
X Ray ◽  
Low Temperature Co Oxidation ◽  
Temperature Programmed ◽  
Adsorption Desorption

AbstractA series of CuO/CeO2 catalysts were successfully synthesized via solution combustion method (SCS) using different fuels and tested for CO oxidation. The catalysts were characterized by energy-dispersive X-ray analysis (EDXA), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), N2 adsorption-desorption isotherms and H2 temperature-programmed reduction (H2-TPR). It was found that the used fuels strongly affected the characterization and the low-temperature reduction behavior of CuO/CeO2 catalysts. The CuO/CeO2-urea catalyst exhibited higher catalytic activity toward CO oxidation (t50=120∘C, t100=159∘C) than the 5 other synthesized catalysts. In addition, the CuO/CeO2-urea catalyst displayed high stability for CO oxidation during five cycles and water resistance. The enhanced catalytic CO oxidation of the synthesized samples can be attributed by a combination of factors, such as smaller crystallite size, higher specific surface area, larger amount of amorphous copper(II) oxide, more mesoporous and uniform spherical-like structure. These findings are worth considering in order to continue the study of the CuO/CeO2 catalyst with low-temperature CO oxidation.

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.

Preparation and Catalytic Performance of Ti(SO4)2/γ-Al2O3 Catalysts for Oligomerization of 1-Butene

2013 ◽  
Vol 634-638 ◽  
pp. 696-700
Author(s):  
Lin Jiu Xiao ◽  
Peng Li ◽  
Yong Gang Sheng
Keyword(s):  
Heat Treatment ◽  
Physicochemical Properties ◽  
Heat Treatment Temperature ◽  
Catalytic Performance ◽  
Treatment Temperature ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Isothermal Adsorption ◽  
X Ray ◽  
Adsorption Desorption

A series of Ti(SO4)2/γ-Al2O3 catalysts were prepared by impregnation method and the catalytic performance of these catalysts in 1-butene oligomerization was investigated. The heat treatment temperature played great influences on the catalytic performance of these catalysts in the oligomerization. 90.1 wt.% conversion of 1-butene and 92.2 wt.% selectivity of dimers were obtained on Ti(SO4)2/γ-Al2O3(450) catalyst at 80 °C, 1.0 Mpa and LHSV=0.6 h−1. The heat treatment temperature determined the crystallinity of TiOSO4 and specific surface area of these catalysts, which affected the catalytic performance of these catalysts in 1-butene oligomerization. In addition, the physicochemical properties of these catalysts were comparatively characterized by powder X-ray diffraction (XRD), N2 isothermal adsorption-desorption techniques.

scholarly journals High Active Co/Mg1-xCex3+O Catalyst: Effects of Metal-Support Promoter Interactions on CO2 Reforming of CH4 Reaction

2021 ◽  
Vol 16 (1) ◽  
pp. 97-110
Author(s):  
Faris A. Jassim Al-Doghachi ◽  
Diyar M. A. Murad ◽  
Huda S. Al-Niaeem ◽  
Salam H. H. Al-Jaberi ◽  
Surahim Mohamad ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Dry Reforming Of Methane ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Co2 Reforming Of Ch4 ◽  
Temperature Programmed

Co/Mg1−XCe3+XO (x = 0, 0.03, 0.07, 0.15; 1 wt% cobalt each) catalysts for the dry reforming of methane (DRM) reaction were prepared using the co-precipitation method with K2CO3 as precipitant. Characterization of the catalysts was achieved by X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), X-ray photoelectron spectroscopy (XPS), temperature programmed reduction (H2-TPR), Brunauer–Emmett–Teller (BET), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA). The role of several reactant and catalyst concentrations, and reaction temperatures (700–900 °C) on the catalytic performance of the DRM reaction was measured in a tubular fixed-bed reactor under atmospheric pressure at various CH4/CO2 concentration ratios (1:1 to 2:1). Using X-ray diffraction, a surface area of 19.2 m2.g−1 was exhibited by the Co/Mg0.85Ce3+0.15O catalyst and MgO phase (average crystallite size of 61.4 nm) was detected on the surface of the catalyst. H2 temperature programmed reaction revealed a reduction of CoO particles to metallic Co0 phase. The catalytic stability of the Co/Mg0.85Ce3+0.15O catalyst was achieved for 200 h on-stream at 900 °C for the 1:1 CH4:CO2 ratio with an H2/CO ratio of 1.0 and a CH4, CO2 conversions of 75% and 86%, respectively. In the present study, the conversion of CH4 was improved (75%–84%) when conducting the experiment at a lower flow of oxygen (1.25%). Finally, the deposition of carbon on the spent catalysts was analyzed using TEM and Temperature programmed oxidation-mass spectroscopy (TPO-MS) following 200 h under an oxygen stream. Better anti-coking activity of the reduced catalyst was observed by both, TEM, and TPO-MS analysis. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA   License (https://creativecommons.org/licenses/by-sa/4.0). 

scholarly journals Effect of Cobalt on Nickel Oxide Toward Reduction Behaviour in Hydrogen and Carbon Monoxide Atmosphere

2020 ◽  
Vol 1010 ◽  
pp. 373-378
Author(s):  
Norliza Dzakaria ◽  
Maratun Najiha Abu Tahari ◽  
Salma Samidin ◽  
Tengku Shafazila Tengku Saharuddin ◽  
Fairous Salleh ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Nickel Oxide ◽  
Reduction Process ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reduction Behaviour ◽  
One Step ◽  
Temperature Programmed ◽  
Co Doped

The reduction behaviour of cobalt doped with nickel oxide and undoped nickel oxide (NiO) by hydrogen (H2) in nitrogen (20%, v/v) and carbon monoxide (CO) in nitrogen (40%, v/v) atmospheres have been investigated by temperature programmed reduction (TPR). The phases formed of partially and completely reduced samples were characterized by X-ray diffraction spectroscopy (XRD). TPR results indicate that the reduction of Co doped and undoped nickel oxide in both reductants proceed in one step reduction (NiO → Ni) without intermediate. TPR results also suggested that by adding Co metal into NiO, the reduction to metallic Ni by both reductant gaseous give different intensity of the peak. The reduction process of Co and undoped NiO become faster when H2 was used as a reductant. Furthermore, in H2 atmosphere, Co-NiO give complete reduction to metallic Ni at 700 °C. Meanwhile, XRD analysis indicated that NiO without Co composed better crystallite phases of NiO with higher intensity.

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.

Study of Preparation, Characterization and Temperature-Programmed Reduction of NiO-ZnO Binary Materials

2013 ◽  
Vol 664 ◽  
pp. 515-520
Author(s):  
Chih Wei Tang ◽  
Jiunn Jer Hwang ◽  
Shie Hsiung Lin ◽  
Chin Chun Chung
Keyword(s):  
Weight Percent ◽  
Precipitation Method ◽  
Temperature Programmed Reduction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Surface Areas ◽  
Temperature Programmed ◽  
Co Precipitation ◽  
Adsorption Desorption

The NiO-ZnO binary materials had been prepared by co-precipitation method. The weight percent of nickel of NiO-ZnO materials were 5, 10 and 20; they were pretreated under air at temperature of 300, 500 and 700°C, respectively. The characterization of NiO-ZnO materials were the thermal gravity analysis(TGA), X-ray diffraction(XRD), N2 adsorption-desorption at 77K, scaning electron microscope(SEM) and temperature-programmed reduction(TPR). The results revealed that surface areas of NiO-ZnO materials order from large to small were 20NiZn(OH)x(66 m2·g-1) > 10NiZn(OH)x(34 m2·g-1) > 5NiZn(OH)x(9 m2·g-1) after being calcined at the temperature of 500°C. Further, NiO-ZnO materials had two main reductive peaks at 390-415°C and 560-657°C, respectively. In all NiO-ZnO materials, 20NiZn(OH)x-C500 material had the highest surface area and the best interaction between NiO and ZnO.

scholarly journals Promotion Effect of CaO Modification on Mesoporous Al2O3-Supported Ni Catalysts for CO2Methanation

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Wen Yang ◽  
Yanyan Feng ◽  
Wei Chu
Keyword(s):  
Surface Coverage ◽  
Temperature Programmed Desorption ◽  
Impregnation Method ◽  
Nio Nanoparticles ◽  
X Ray Diffraction ◽  
Ni Catalysts ◽  
X Ray ◽  
Temperature Programmed ◽  
Adsorption Desorption ◽  
Supported Ni

The catalysts Ni/Al2O3and CaO modified Ni/Al2O3were prepared by impregnation method and applied for methanation of CO2. The catalysts were characterized by N2adsorption/desorption, temperature-programmed reduction of H2(H2-TPR), X-ray diffraction (XRD), and temperature-programmed desorption of CO2and H2(CO2-TPD and H2-TPD) techniques, respectively. TPR and XRD results indicated that CaO can effectively restrain the growth of NiO nanoparticles, improve the dispersion of NiO, and weaken the interaction between NiO and Al2O3. CO2-TPD and H2-TPD results suggested that CaO can change the environment surrounding of CO2and H2adsorption and thus the reactants on the Ni atoms can be activated more easily. The modified Ni/Al2O3showed better catalytic activity than pure Ni/Al2O3. Ni/CaO-Al2O3showed high CO2conversion especially at low temperatures compared to Ni/Al2O3, and the selectivity to CH4was very close to 1. The high CO2conversion over Ni/CaO-Al2O3was mainly caused by the surface coverage by CO2-derived species on CaO-Al2O3surface.

scholarly journals SYNTHESIS, CHARACTERIZATION, AND APPLICATION OF ZnO/ZSM-5 AS CATALYST IN THE CRACKING PROCESS OF PALM METHYL ESTERS

2021 ◽  
pp. 1-8
Author(s):  
Nina Haryani ◽  
Taslim Taslim ◽  
Irvan ◽  
Renita Manurung ◽  
Rondang Tambun
Keyword(s):  
Alternative Fuels ◽  
Methyl Esters ◽  
Environmentally Friendly ◽  
Impregnation Method ◽  
X Ray Diffraction ◽  
Wet Impregnation ◽  
X Ray ◽  
Temperature Programmed ◽  
Cracking Process ◽  
Adsorption Desorption

Biofuels as environmentally friendly alternative fuels such as biogasoline, biokerosene and others are generally obtained through a cracking process and take place more effectively to attend a catalyst. In this study, the synthesis of ZnO/ZSM-5 aims to obtain a catalyst that can be used in the cracking process of Palm Methyl Esters (PME) into hydrocarbon fuels especially biogasoline. This catalyst is environmentally friendly, easy to separate, has good selectivity, and can increase the conversion of cracking products. The wet impregnation method followed by drying and calcination is the method used to synthesize the catalyst. Furthermore, several analyzes were carried out to determine the characteristics of the catalyst. The analysis is the Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), X-Ray Diffraction (XRD), N2 adsorption-desorption with BET-BJH, Temperature Programmed Desorption-NH3 (TPD-NH3) and the Temperature Programmed Reduction (TPR). Based on synthesis results obtained ZnO/ZSM-5 catalyst with ZnO content of 11.77 wt%, 13.61 wt% and 18.22 wt%. The use of this catalyst in the cracking process can result in the conversion of liquid fuel by 88.57%, heavy hydrocarbon (8.57%) and gas product (2.86%).

Preparation and Characterization of Hierarchical Pore Molecular Sieve with Large Pore Size

2016 ◽  
Vol 859 ◽  
pp. 62-67
Author(s):  
Min Li ◽  
Dong Liu ◽  
Yue Lun Wang ◽  
Ya Dong Zhang ◽  
Ran Yu ◽  
...  
Keyword(s):  
Pore Size ◽  
Molecular Sieves ◽  
Fixed Bed ◽  
Cobalt Nitrate ◽  
Fixed Bed Reactor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hierarchical Pore ◽  
Adsorption Desorption

A series of hierarchical pore molecular sieves (HPMSs) with pore size up to 6.0 nm were prepared using triblock copolymer (P123) as mesoporous template agent and characterized by N2 adsorption-desorption. Cobalt-loaded catalysts were prepared by impregnating cobalt nitrate onto HPMSs and characterized by X-ray diffraction and scanning electron microscopy. The result indicates that mesopore size of HPMS increased along with the increment of the amount of P123. The selectivity of the catalysts for Fischer-Tropsch synthesis was evaluated in a fixed-bed reactor, and the results show that the selectivity of C12+ hydrocarbons is increased with the increment of the pore size.

Sign in / Sign up

Export Citation Format

Share Document