scholarly journals High Selectivity and Stability of Nickel Catalysts for CO2 Methanation: Support Effects

Catalysts ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 24 ◽  
Author(s):  
Jeremías Martínez ◽  
Edgar Hernández ◽  
Salvador Alfaro ◽  
Ricardo López Medina ◽  
Guadalupe Valverde Aguilar ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Fixed Bed ◽  
Tetragonal Zirconia ◽  
Nickel Catalysts ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Methane Formation ◽  
Co2 Methanation ◽  
X Ray

In this work, we present an investigation concerning the evaluation of the catalytic properties of Ni nanoparticles supported on ZrO2, SiO2, and MgAl2O4 for CO2 hydrogenation to methane. The supports were prepared by coprecipitation and sol-gel, while Ni was incorporated by impregnation (10–20 wt %). X-ray diffraction, nitrogen physisorption, temperature-programmed reduction, H2 pulse chemisorption, Raman spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy were the main characterization techniques employed. A laboratory fixed-bed reactor operated at atmospheric pressure, a temperature range of 350–500 °C, and a stoichiometric H2/CO2 molar ratio was used for catalyst evaluation. The most outstanding results were obtained with nickel catalysts supported on ZrO2 with CO2 conversions of close to 60%, and selectivity to methane formation was 100% on a dry basis, with high stability after 250 h of reaction time. The majority presence of tetragonal zirconia, as well as the strong Ni–ZrO2 interaction, were responsible for the high catalytic performance of the Ni/ZrO2 catalysts.

Synthesis of CeO2 Supported BaCoO3 Perovskites for Chemical-Looping Methane Reforming to Syngas and Hydrogen

2017 ◽  
Author(s):  
Haoran Ding ◽  
Yongqing Xu ◽  
Linyi Xiang ◽  
Qiyao Wang ◽  
Cheng Shen ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Fixed Bed ◽  
Gas Production ◽  
Fixed Bed Reactor ◽  
Methane Reforming ◽  
Chemical Looping ◽  
X Ray ◽  
Syngas Production ◽  
Fuel Reactor

In order to reduce the hotspots in partial oxidation of methane, CeO2 supported BaCoO3 perogvskite-type oxides were synthesized using a sol-gel method and applied in chemical-looping steam methane reforming (CL-SMR). The synthesized BaCoO3-CeO2 was characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). XRD and XPS results suggested that the obtained BaCoO3 was pure crystalline perovskite, its crystalline structure and lattice oxygen could regenerate after calcining. The reactivity of perovskite-type oxides in CL-SMR was evaluated using a fixed-bed reactor. Gas production rates and H2/CO ratios showed that the optimal reaction temperature was about 860 °C and the properly reaction time in fuel reactor was about 180s when Weight Hourly Space Velocity (WHSV) was 23.57 h−1. The syngas production in fuel reactor were 265.11 ml/g, hydrogen production in reforming reactor were 82.53 ml/g. (CSPE)

scholarly journals Nickel Supported on Mesoporous Zirconium Oxide by Atomic Layer Deposition: Initial Fixed-Bed Reactor Study

2018 ◽  
Author(s):  
Riikka Puurunen ◽  
Pauline Voigt ◽  
Eero Haimi ◽  
Jouko Lahtinen ◽  
You Wayne Cheah ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Atomic Layer ◽  
Nickel Catalysts ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
X Ray ◽  
Fluorescence Measurements ◽  
Layer Deposition

Atomic layer deposition (ALD) is gaining attention as a catalyst preparation method able to produce metal (oxide, sulphide, etc.) nanoparticles of uniform size down to single atoms. This work reports our initial experiments to support nickel on mesoporous zirconia. Nickel (2,2,6,6-tetramethyl-3,5-heptanedionato)2 [Ni(thd)2] was reacted in a fixed-bed ALD reactor with zirconia, characterised with BET surface area of 72 m2/g and mean pore size of 14 nm. According to X-ray fluorescence measurements, the average nickel loading on the top part of the support bed was on the order of 1 wt-%, corresponding to circa one nickel atom per square nanometre. Cross-sectional scanning electron microscopy combined with energy-dispersive spectroscopy confirmed that in the top part of the fixed support bed, nickel was distributed throughout the zirconia particles. X-ray photoelectron spectroscopy indicated the nickel oxidation state to be two. Organic thd ligands remained complete on the surface after the Ni(thd)2 reaction with zirconia, as followed with diffuse reflectance infrared Fourier transform spectroscopy. The ligands could be fully removed by oxidation at 400 °C. These initial results indicate that nickel catalysts on zirconia can likely be made by ALD. Before catalytic testing, in addition to increasing the nickel loading by repeated ALD cycles, optimization of the process parameters is required to ensure uniform distribution of nickel throughout the support bed and within the zirconia particles.

scholarly journals Nickel Supported on Mesoporous Zirconium Oxide by Atomic Layer Deposition: Initial Fixed-Bed Reactor Study

2018 ◽  
Author(s):  
Riikka Puurunen ◽  
Pauline Voigt ◽  
Eero Haimi ◽  
Jouko Lahtinen ◽  
You Wayne Cheah ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Atomic Layer ◽  
Nickel Catalysts ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
X Ray ◽  
Fluorescence Measurements ◽  
Layer Deposition

Atomic layer deposition (ALD) is gaining attention as a catalyst preparation method able to produce metal (oxide, sulphide, etc.) nanoparticles of uniform size down to single atoms. This work reports our initial experiments to support nickel on mesoporous zirconia. Nickel (2,2,6,6-tetramethyl-3,5-heptanedionato)2 [Ni(thd)2] was reacted in a fixed-bed ALD reactor with zirconia, characterised with BET surface area of 72 m2/g and mean pore size of 14 nm. According to X-ray fluorescence measurements, the average nickel loading on the top part of the support bed was on the order of 1 wt-%, corresponding to circa one nickel atom per square nanometre. Cross-sectional scanning electron microscopy combined with energy-dispersive spectroscopy confirmed that in the top part of the fixed support bed, nickel was distributed throughout the zirconia particles. X-ray photoelectron spectroscopy indicated the nickel oxidation state to be two. Organic thd ligands remained complete on the surface after the Ni(thd)2 reaction with zirconia, as followed with diffuse reflectance infrared Fourier transform spectroscopy. The ligands could be fully removed by oxidation at 400 °C. These initial results indicate that nickel catalysts on zirconia can likely be made by ALD. Before catalytic testing, in addition to increasing the nickel loading by repeated ALD cycles, optimization of the process parameters is required to ensure uniform distribution of nickel throughout the support bed and within the zirconia particles.

scholarly journals Nickel Supported on Mesoporous Zirconium Oxide by Atomic Layer Deposition: Initial Fixed-Bed Reactor Study

2018 ◽  
Author(s):  
Riikka Puurunen ◽  
Pauline Voigt ◽  
Eero Haimi ◽  
Jouko Lahtinen ◽  
You Wayne Cheah ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Atomic Layer ◽  
Nickel Catalysts ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
X Ray ◽  
Fluorescence Measurements ◽  
Layer Deposition

Atomic layer deposition (ALD) is gaining attention as a catalyst preparation method able to produce metal (oxide, sulphide, etc.) nanoparticles of uniform size down to single atoms. This work reports our initial experiments to support nickel on mesoporous zirconia. Nickel (2,2,6,6-tetramethyl-3,5-heptanedionato)2 [Ni(thd)2] was reacted in a fixed-bed ALD reactor with zirconia, characterised with BET surface area of 72 m2/g and mean pore size of 14 nm. According to X-ray fluorescence measurements, the average nickel loading on the top part of the support bed was on the order of 1 wt-%, corresponding to circa one nickel atom per square nanometre. Cross-sectional scanning electron microscopy combined with energy-dispersive spectroscopy confirmed that in the top part of the fixed support bed, nickel was distributed throughout the zirconia particles. X-ray photoelectron spectroscopy indicated the nickel oxidation state to be two. Organic thd ligands remained complete on the surface after the Ni(thd)2 reaction with zirconia, as followed with diffuse reflectance infrared Fourier transform spectroscopy. The ligands could be fully removed by oxidation at 400 °C. These initial results indicate that nickel catalysts on zirconia can likely be made by ALD. Before catalytic testing, in addition to increasing the nickel loading by repeated ALD cycles, optimization of the process parameters is required to ensure uniform distribution of nickel throughout the support bed and within the zirconia particles.

scholarly journals Lead-Free BNT–BT0.08/CoFe2O4 Core–Shell Nanostructures with Potential Multifunctional Applications

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 672
Author(s):  
Marin Cernea ◽  
Roxana Radu ◽  
Harvey Amorín ◽  
Simona Gabriela Greculeasa ◽  
Bogdan Stefan Vasile ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Molar Ratio ◽  
Transmission Electron Microscopy Data ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Two Phase ◽  
X Ray ◽  
Shell Nanostructures

Herein we report on novel multiferroic core–shell nanostructures of cobalt ferrite (CoFe2O4)–bismuth, sodium titanate doped with barium titanate (BNT–BT0.08), prepared by a two–step wet chemical procedure, using the sol–gel technique. The fraction of CoFe2O4 was varied from 1:0.5 to 1:1.5 = BNT–BT0.08/CoFe2O4 (molar ratio). X–ray diffraction confirmed the presence of both the spinel CoFe2O4 and the perovskite Bi0.5Na0.5TiO3 phases. Scanning electron microscopy analysis indicated that the diameter of the core–shell nanoparticles was between 15 and 40 nm. Transmission electron microscopy data showed two–phase composite nanostructures consisting of a BNT–BT0.08 core surrounded by a CoFe2O4 shell with an average thickness of 4–7 nm. Cole-Cole plots reveal the presence of grains and grain boundary effects in the BNT–BT0.08/CoFe2O4 composite. Moreover, the values of the dc conductivity were found to increase with the amount of CoFe2O4 semiconductive phase. Both X-ray photoelectron spectroscopy (XPS) and Mössbauer measurements have shown no change in the valence of the Fe3+, Co2+, Bi3+ and Ti4+ cations. This study provides a detailed insight into the magnetoelectric coupling of the multiferroic BNT–BT0.08/CoFe2O4 core–shell composite potentially suitable for magnetoelectric applications.

Synthesis, Characterization and Photocatalytic Activity of Nb-Doped TiO2 Nanoparticles

2012 ◽  
Vol 455-456 ◽  
pp. 110-114 ◽  
Author(s):  
Xuan Dong Li ◽  
Xi Jiang Han ◽  
Wen Ying Wang ◽  
Xiao Hong Liu ◽  
Yan Wang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Doped Tio2 ◽  
X Ray ◽  
Vis Spectroscopy

Nb-doped TiO2 powders with different concentrations of Nb have been synthesized by a sol-gel method and characterized by a series of technologies including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy. The photocatalytic activity of Nb-doped TiO2 is evaluated by degradation efficiency of methyl orange in aqueous solution. The results indicate that the photocatalytic activity of Nb-doped TiO2 synthesized with a Nb/Ti molar ratio of 5% is higher than that of TiO2 under the visible light.

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 CO2 Methanation of Biogas over 20 wt% Ni-Mg-Al Catalyst: on the Effect of N2, CH4, and O2 on CO2 Conversion Rate

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1201
Author(s):  
Danbee Han ◽  
Yunji Kim ◽  
Hyunseung Byun ◽  
Wonjun Cho ◽  
Youngsoon Baek
Keyword(s):  
Reaction Temperature ◽  
Photoelectron Spectroscopy ◽  
Conversion Rate ◽  
Space Velocity ◽  
Molar Ratio ◽  
Co2 Conversion ◽  
X Ray Diffraction ◽  
Co2 Methanation ◽  
X Ray ◽  
Ch4 Production

Biogas contains more than 40% CO2 that can be removed to produce high quality CH4. Recently, CH4 production from CO2 methanation has been reported in several studies. In this study, CO2 methanation of biogas was performed over a 20 wt% Ni-Mg-Al catalyst, and the effects of CO2 conversion rate and CH4 selectivity were investigated as a function of CH4, O2, H2O, and N2 compositions of the biogas. At a gas hourly space velocity (GHSV) of 30,000 h−1, the CO2 conversion rate was ~79.3% with a CH4 selectivity of 95%. In addition, the effects of the reaction temperature (200–450 °C), GHSV (21,000–50,000 h−1), and H2/CO2 molar ratio (3–5) on the CO2 conversion rate and CH4 selectivity over the 20 wt% Ni-Mg-Al catalyst were evaluated. The characteristics of the catalyst were analyzed using Brunauer–Emmett–Teller surface area analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The catalyst was stable for approximately 200 h at a GHSV of 30,000 h−1 and a reaction temperature of 350 °C. CO2 conversion and CH4 selectivity were maintained at 75% and 93%, respectively, and the catalyst was therefore concluded to exhibit stable activity.

Effect of the Reduction Temperature on Nickel Phosphide Catalyst Structure and Catalytic Activity for Hydrodesulfurization

2014 ◽  
Vol 1025-1026 ◽  
pp. 782-786 ◽  
Author(s):  
Hua Song ◽  
Fu Yong Zhang ◽  
Zai Shun Jin ◽  
Huai Yuan Wang ◽  
Yan Ji Zhu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Space Velocity ◽  
Fixed Bed Reactor ◽  
Reduction Temperature ◽  
Catalyst Structure ◽  
X Ray ◽  
Weight Hourly Space Velocity ◽  
Transmission Electron ◽  
Nickel Phosphate

Ni2P/TiO2-Al2O3catalysts were prepared by impregnation of nickel phosphate precursors followed by reduction in hydrogen. The catalysts were characterized by X-ray diffraction (XRD), N2-adsorption specific surface area measurements (BET), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetry differential thermal analysis (TG-DTA). The effects of reduction temperature on catalyst structure and HDS activity were studied using a lab-scale continuous flow fixed-bed reactor.. The results indicated that the catalyst prepared with reduction temperature of 973 K exhibited the best performance. At a reaction temperature of 606 K, a pressure of 3.0 MPa, a hydrogen/oil ratio of 500 (V/V), and a weight hourly space velocity (WHSV) of 2.0 h-1, the conversion of DBT HDS was 96.0%.

scholarly journals Catalytic Dry Reforming and Cracking of Ethylene for Carbon Nanofilaments and Hydrogen Production Using a Catalyst Derived from a Mining Residue

Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1069 ◽  
Author(s):  
Abir Azara ◽  
El-Hadi Benyoussef ◽  
Faroudja Mohellebi ◽  
Mostafa Chamoumi ◽  
François Gitzhofer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fixed Bed ◽  
Dry Reforming ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Spent Catalysts ◽  
Temperature Programmed

In this study, iron-rich mining residue (UGSO) was used as a support to prepare a new Ni-based catalyst via a solid-state reaction protocol. Ni-UGSO with different Ni weight percentages wt.% (5, 10, and 13) were tested for C2H4 dry reforming (DR) and catalytic cracking (CC) after activation with H2. The reactions were conducted in a differential fixed-bed reactor at 550–750 °C and standard atmospheric pressure, using 0.5 g of catalyst. Pure gases were fed at a molar ratio of C2H4/CO2 = 3 for the DR reaction and C2H4/Ar = 3 for the CC reaction. The flow rate is defined by a GHSV = 4800 mLSTP/h.gcat. The catalyst performance is evaluated by calculating the C2H4 conversion as well as carbon and H2 yields. All fresh, activated, and spent catalysts, as well as deposited carbon, were characterized by Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), temperature programmed reduction (TPR), and thermogravimetric analysis (TGA). The results so far show that the highest carbon and H2 yields are obtained with Ni-UGSO 13% at 750 °C for the CC reaction and at 650 °C for the DR reaction. The deposited carbon was found to be filamentous and of various sizes (i.e., diameters and lengths). The analyses of the results show that iron is responsible for the growth of carbon nanofilaments (CNF) and nickel is responsible for the split of C–C bonds. In terms of conversion and yield efficiencies, the performance of the catalytic formulations tested is proven at least equivalent to other Ni-based catalyst performances described by the literature.

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