Syngas Production from Reforming of Methane with CO2 and O2 over LaNi1–xCoxO3 Perovskites

2014 ◽  
Vol 12 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Alireza Jahangiri ◽  
Hamidreza Aghabozorg ◽  
Hassan Pahlavanzadeh ◽  
Jafar Towfighi
Keyword(s):  
Catalytic Activity ◽  
Atmospheric Pressure ◽  
Sol Gel ◽  
Coke Formation ◽  
Synthesis Method ◽  
Partial Substitution ◽  
Particle Sizes ◽  
Co Doping ◽  
Syngas Production ◽  
Xrd Patterns

Abstract The LaNi1–xCoxO3 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) perovskites were prepared by the citrate sol–gel method. The prepared compounds were characterized by using XRD, BET, ICP, SEM, EDS, TEM, TPR and TGA techniques, under the condition of as-synthesized and used samples. The results showed that the highly homogeneous and pure solids with particle sizes in the range of nanometers were obtained through this synthesis method. The XRD patterns of fresh catalysts indicated the formation of well-crystallized perovskite structure with LaNiO3 and LaCoO3 as the main phases present on the solids depending on the amount of Co-substitution. TPR analysis revealed that the reduction of the solids was more difficult when increasing the degree of substitution (x). The effects of the partial substitution of Ni by Co and reaction temperatures at atmospheric pressure were investigated in the combined reforming of methane with CO2 and O2 (CRM), after reduction of the samples under hydrogen. LaNiO3 exhibited high activity and selectivity without coke formation between all of the studied perovskites. For LaNi1–xCoxO3 perovskites, it was observed a trend to decrease the catalytic activity with increasing the Co-doping level.

Characterization and Catalytic Reactivity of LaNi1-xMgxO3-δ Perovskite Oxides in Reforming of Methane with CO2 and O2

2017 ◽  
Vol 16 (4) ◽  
Author(s):  
Alireza Jahangiri ◽  
Majid Saidi ◽  
Abolfazl Mohammadi ◽  
Mehdi Sedighi
Keyword(s):  
Catalytic Activity ◽  
Surface Area ◽  
Sol Gel ◽  
Synthesis Method ◽  
Sample Surface ◽  
Nano Particles ◽  
Partial Substitution ◽  
Syngas Production ◽  
Highly Active ◽  
Oxide Phases

Abstract A series of Mg doped LaNiO3 nano particles by solids denoted as LaNi1-xMgxO3-δ (x = 0, 0.1, 0.2, 0.4, 0.6, 0.8 and 1) were prepared by the modified citrate sol-gel method and investigated as catalysts for combine reforming of methane (CRM).The resulting oxides were examined by using XRD, BET, ICP, SEM, EDS, TEM, TPR and TGA techniques, under the condition of as-synthesized and used samples. The results showed that highly homogeneous and crystalline oxides with particle sizes in the range of nanometers were obtained through this synthesis method. The XRD patterns of the prepared LaNi1-xMgxO3-δsolids confirmed with increasing Mg amount not only perovskite structure could not form correctly but also the spinel (La2NiO4) and oxide phases (MgO and NiO) are produced on the sample surface. Also according to BET results, the presence of these oxide phases lead to the increase in the surface area of samples .Although, increasing in surface area had not a significant effect in results of activity tests. TPR analysis revealed that the reduction of the prepared samples became more difficult by increasing the degree of substitution (x). The effects of the partial substitution of Ni by Mg and reaction temperatures (600–800 °C) were investigated in CRM process, after reduction of the samples under hydrogen. Although, all catalysts, except LaMgO3, were found to be highly active toward the syngas production during the CRM process but substitution of Ni by Mg could not improve the catalytic activity of the LaNi1-xMgxO3-δ in this process. The catalytic activity in the steady state was found to decrease in the following order: $${\text{LaNi}}{{\text{O}}_{\text{3}}} \gt {\text{LaN}}{{\text{i}}_{{\text{0}}{\text{.4}}}}{\text{M}}{{\text{g}}_{{\text{0}}{\text{.6}}}}{{\text{O}}_{{\text{3 - }}\delta }} \gt {\text{LaN}}{{\text{i}}_{{\text{0}}{\text{.6}}}}{\text{M}}{{\text{g}}_{{\text{0}}{\text{.4}}}}{{\text{O}}_{{\text{3 - }}\delta }} \gt {\text{LaN}}{{\text{i}}_{{\text{0}}{\text{.9}}}}{\text{M}}{{\text{g}}_{{\text{0}}{\text{.1}}}}{{\text{O}}_{{\text{3 - }}\delta }} \gt {\text{LaN}}{{\text{i}}_{{\text{0}}{\text{.8}}}}{\text{M}}{{\text{g}}_{{\text{0}}{\text{.2}}}}{{\text{O}}_{{\text{3 - }}\delta }} \gt {\text{LaMgO3 - }}\delta$$ Of course, according to the TPR and TGA results, the stability of the samples increased and the coke deposits on the catalyst surface decreased with increasing of x, respectively.

Preparation and Characterization of Cu1-xKxFe2O4 Fibers and the Catalytic Activity for Diesel Engine Exhaust Removal

2010 ◽  
Vol 96 ◽  
pp. 135-139
Author(s):  
Cai Rong Gong ◽  
Hai Feng Chen ◽  
Guo Liang Fan ◽  
Chong Lin Song ◽  
Gang Lv
Keyword(s):  
Catalytic Activity ◽  
Sol Gel ◽  
Complex Oxide ◽  
Average Diameter ◽  
Partial Substitution ◽  
High Catalytic Activity ◽  
Engine Exhaust ◽  
Sol Gel Process ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction

A series of complex oxide Cu1-xKxFe2O4 fibers have been prepared via a sol-gel process related electron-spinning procedure, in which x is among 0, 0.05, 0.1 and 0.2 corresponding to the quantity of Cu2+ partial substitution by K+. The average diameter of the fiber was 500 nm. The catalytic activity of the catalysts in removal of NOx and carbon black from diesel exhaust gases were examined in detail using temperature-programmed reaction technique. The results show that after partial substitution of Cu2+ with K+, the catalytic activities have been improved. Cu0.95K0.05Fe2O4 as an optimal catalyst can significantly decrease the ignition temperature (Tig) of the PM, and has high catalytic activity on the removal of NOx.

scholarly journals Effect of Cu F Co-doping on the Properties of AgSnO2 Contact

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2315
Author(s):  
Jing-qin Wang ◽  
Zhou Liu ◽  
Ling Chen ◽  
Shuang-miao Yu ◽  
Yan-cai Zhu
Keyword(s):  
Mechanical Properties ◽  
First Principles ◽  
Formation Energy ◽  
Sol Gel ◽  
Energy Increase ◽  
Electron Effective Mass ◽  
Co Doping ◽  
Series Of Experiments ◽  
Xrd Patterns ◽  
Co Doped

The crystal structures, mechanical properties, and electrical properties of Cu doped SnO2, F doped SnO2, and Cu F co-doped SnO2 were studied by using the first-principles method. Meanwhile, AgSnO2, AgSnO2-F, AgSnO2-Cu, and AgSnO2-Cu-F contacts were prepared by using the sol-gel method for a series of experiments to verify the theoretical analysis. According to the XRD patterns, the doping does not change the structure of SnO2, but increases its lattice constant and volume. Compared with the single-doped system, the doping formation energy of Cu F co-doped system is the smallest and the structure is more stable. Among the three groups of doping systems, the Cu F co-doped system has the highest shear modulus, Young’s modulus, hardness, and Debye temperature, and its mechanical properties and wear resistance are relatively best, and the melting point is also the highest. Cu F co-doping can further narrow the band gap of SnO2, reduce the electron effective mass and donor ionization energy, increase the electron mobility, and further enhance the conductivity of SnO2. The wetting angle of SnO2-Cu-F sample with Ag liquid is 1.15°, which indicates that Cu and F co-doping can significantly improve the wettability of SnO2 and Ag liquid. AgSnO2-Cu-F contact has a hardness of 82.03 HV, an electrical conductivity of 31.20 mS⋅m−1, and a contact resistance of 1.048 mΩ. Cu F co-doping can improve the shortcomings of AgSnO2 contact properties.

scholarly journals Effect of Direct Reduction Treatment on Pt–Sn/Al2O3 Catalyst for Propane Dehydrogenation

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 446 ◽  
Author(s):  
Jae-Won Jung ◽  
Won-Il Kim ◽  
Jeong-Rang Kim ◽  
Kyeongseok Oh ◽  
Hyoung Lim Koh
Keyword(s):  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Direct Reduction ◽  
Coke Formation ◽  
Catalytic Performance ◽  
Propane Dehydrogenation ◽  
X Ray ◽  
Transmission Electron ◽  
Calcination Step ◽  
Xrd Patterns

Pt–Sn/Al2O3 catalysts were prepared by the direct reduction method at temperatures from 450 to 900 °C, denoted as an SR series (SR450 to SR900 according to reduction temperature). Direct reduction was performed immediately after catalyst drying without a calcination step. The activity of SR catalysts and a conventionally prepared (Cal600) catalyst were compared to evaluate its effect on direct reduction. Among the SR catalysts, SR550 showed overall higher conversion of propane and propylene selectivity than Cal600. The nano-sized dispersion of metals on SR550 was verified by transmission electron microscopy (TEM) observation. The phases of the bimetallic Pt–Sn alloys were examined by X-ray diffraction, TEM, and energy dispersive X-ray spectroscopy (EDS). Two characteristic peaks of Pt3Sn and PtSn alloys were observed in the XRD patterns, and these phases affected the catalytic performance. Moreover, EDS confirmed the formation of Pt3Sn and PtSn alloys on the catalyst surface. In terms of catalytic activity, the Pt3Sn alloy showed better performance than the PtSn alloy. Relationships between the intermetallic interactions and catalytic activity were investigated using X-ray photoelectron spectroscopy. Furthermore, qualitative analysis of coke formation was conducted after propane dehydrogenation using differential thermal analysis.

scholarly journals Electrochemical Properties of Ce0.5Sr0.5 (Co0.8Fe0.2)1−xZrxO3−δ Cathode Materials for Low Intermediate Temperature Solid Oxide Fuel Cells (LIT-SOFCs) Synthesized by Sol-Gel Method

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Beyene Tesfaw Ayalew ◽  
P. Vijay Bhaskar Rao
Keyword(s):  
Electrochemical Properties ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Electronic Conductivity ◽  
Partial Substitution ◽  
Sem Images ◽  
Gel Method ◽  
Sol Gel Method ◽  
Crystallite Sizes ◽  
Xrd Patterns

Ce0.5Sr0.5 (Co0.8Fe0.2)1−x ZrxO3−δ (CSCFZ) powders were synthesized by the sol-gel method and characterized to study structural and electrochemical properties. X-ray diffractometer (XRD) patterns of all samples give nanosized particles of a high-degree crystalline cathode having a cubic-type perovskite structure of space group Pm-3m with the existence of oxygen vacancies in the lattices. The results have the perovskite phase with average crystallite sizes of 26.57 nm, 18.14 nm, 18.13 nm, and 18.12 nm with porosities of 9.93%, 9.87%, 9.50%, and 9.08% for x = 0, 0.1, 0.15, and 0.2, respectively. Scanning electron microscope (SEM) micrographs showed the presence of pores on the microstructure. Average grain sizes of prepared samples found from SEM images were in the range of 105.30–183.02 nm. The partial substitution of zirconium at the B-site shows more stable materials than the host without decreasing the porosity that much. The results of electronic conductivity analyzed by the four-probe dc technique show that the conductivity of synthesized materials increases with the increment of both dopant concentration and temperature by the decrement of area specific resistances. The electrical conductivity of CSCFZ steadily increased with the increment of temperature which reached 42.76 Scm−1 at around 450°C.

scholarly journals The influence of BaGeO3 on the properties of Ba(Ti1−xSx)O3 ceramics on the basis of sol-gel powders

2019 ◽  
Author(s):  
Roberto Köferstein
Keyword(s):  
Phase Transition ◽  
Ferroelectric Phase Transition ◽  
Ferroelectric Phase ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Synthesis Method ◽  
Particle Sizes ◽  
Dielectric Measurements ◽  
Sintering Additive ◽  
Phase Transition Temperatures

Ba(Ti1−x−y SnxGey )O3 (BTSG-x-y; x = 0, 0.05; y = 0–0.05) powders were synthesized by a sol-gel (SG) method and for comparative purposes also by a mixed-oxide (MO) method. In this system, BaGeO3 functions as sintering additive. Due to smaller particle sizes of the SG powders a higher sintering activity was found, which resulted in reduced grain growth and in a more homogenous grain size distribution for the corresponding ceramics. The dependence on the paraelectric ⇆ ferroelectric phase transition, i.e. the phase transition temperature, thewidth of the transition region and completeness were examined by dielectric measurements,DTA as well as by SEM, EDX and XRD investigations with respect to the BaGeO3 content, synthesis method and sintering temperature. The phase transition temperatures of the SG ceramics are remarkably higher than those of the MO ceramics with the same nominal compositions. The reason is a lower tin concentration within the grains of SG ceramics as confirmed by EDX and XRD investigations. The presence of BaGeO3 in barium titanate–stannate system on the basis of a SG method caused an improved incorporation of tin in theBaTiO3 lattice.

Influence of Calcination Temperature on Synthesis of Magnetite (Fe3O4) Nanoparticles by Sol-Gel Method

2014 ◽  
Vol 979 ◽  
pp. 208-211 ◽  
Author(s):  
Apichaya Worawong ◽  
Tula Jutarosaga ◽  
Wandee Onreabroy
Keyword(s):  
Magnetic Nanoparticles ◽  
Calcination Temperature ◽  
Sol Gel ◽  
Ferric Nitrate ◽  
Particle Sizes ◽  
Sem Images ◽  
Gel Method ◽  
Sol Gel Method ◽  
Size And Morphology ◽  
Xrd Patterns

Magnetite (Fe3O4) nanoparticles were successfully synthesized by the sol-gel method from ferric nitrate-EG (EG=ethylene glycol) gel. The precursors were calcined in argon under an atmospheric pressure at the temperatures varied from 400°C to 500°C. The synthesized magnetic nanoparticles were characterized by X-ray diffractrometer (XRD), field emission scanning electron microscope (FE-SEM) and vibrating sample magnetometer (VSM). The XRD patterns of powder calcined temperature at 400๐C showed clearer Fe3O4phase than those calcined at other temperatures. The particle size and morphology of magnetic nanoparticles were studied using FE-SEM. The FE-SEM images showed that the particle sizes varied from 30-108 nm. The particle sizes increased with the increase of calcination temperature. VSM measurements indicated that the Fe3O4nanoparticles were soft ferrite with the maximum magnetization (Mm) and coercivity (Hc) of 35 emu/g and 17 Oe, respectively.

scholarly journals Photothermal catalytic activity of combustion synthesized LaCoxFe1−xO3 (0 ≤ x ≤ 1) perovskite for CO2 reduction with H2O to CH4 and CH3OH

RSC Advances ◽  
2017 ◽  
Vol 7 (73) ◽  
pp. 45949-45959 ◽  
Author(s):  
Lijuan Xu ◽  
Minh Ngoc Ha ◽  
Qiangsheng Guo ◽  
Lichao Wang ◽  
Yanan Ren ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Sol Gel ◽  
Co2 Reduction ◽  
Co Doping ◽  
Gel Combustion ◽  
Combustion Route

A range of LaCoxFe1−xO3 perovskites with different Co-doping at the B-site were successfully synthesized via a sol–gel combustion route.

Syngas production by methane tri-reforming: Effect of Ni/CeO2 synthesis method on oxygen vacancies and coke formation

2022 ◽  
Vol 56 ◽  
pp. 101853
Author(s):  
Chayene Gonçalves Anchieta ◽  
Elisabete Moreira Assaf ◽  
José Mansur Assaf
Keyword(s):  
Oxygen Vacancies ◽  
Coke Formation ◽  
Synthesis Method ◽  
Syngas Production

scholarly journals Syngas Production via Methane Dry Reforming over La-Ni-Co and La-Ni-Cu Catalysts with Spinel and Perovskite Structures

2020 ◽  
Vol 15 (3) ◽  
pp. 885-897
Author(s):  
Hassiba Messaoudi ◽  
Sébastien Thomas ◽  
Samira Slyemi ◽  
Abdelhamid Djaidja ◽  
Akila Barama
Keyword(s):  
Sol Gel ◽  
Xrd Analysis ◽  
H2 Production ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Partial Substitution ◽  
Activation Temperature ◽  
Syngas Production ◽  
Spent Catalysts ◽  
Spinel Structures

In this paper, the catalytic properties of La-Ni-M (M = Co, Cu) based materials in dry reforming of methane (DRM) for syngas (CO + H2) production, were studied in the temperature range 773−1073 K. The LaNi0.9M0.1O3 and La2Ni0.9M0.1O4 (M = Co, Cu and Ni/M = 0.9/0.1) catalysts were prepared by partial substitution of Ni by Co or Cu using sol-gel method then characterized by XRD, H2-TPR and N2 physisorption. The XRD analysis of fresh catalysts showed, in the case of Co-substitution, the formation of La-Ni and La-Co perovskite and spinel structures, while only LaNiO3 and La2NiO4 phases were observed for the Cu-substituted samples. The substitution of these two structures by copper decreases the reduction temperature compared to cobalt. The reactivity results showed that the partial substitution of nickel by copper decreases the methane activation temperature, whereas a better stability of catalytic activity and syngas production was obtained via the cobalt-substituted catalysts, which is due to a synergistic effect between Ni and Co. The TPO analysis carried out on the spent catalysts indicated that the lowest carbon deposition was obtained for the cobalt substituted samples. Copyright © 2020 BCREC Group. All rights reserved 

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