scholarly journals Effect of Molybdenum on the Activity Temperature Enlarging of Mn-Based Catalyst for Mercury Oxidation

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 147
Author(s):  
Bo Zhao ◽  
Xiaojiong Zhao ◽  
Yangshuo Liang ◽  
Yu Wang ◽  
Linbo Qin ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Optimal Temperature ◽  
Mercury Oxidation ◽  
X Ray ◽  
Optimal Temperature Range ◽  
Different Temperatures ◽  
Activity Temperature ◽  
Oxidation Efficiency

The MnO2/TiO2 (TM5) catalyst modified by molybdenum was used for mercury oxidation at different temperatures in a fixed-bed reactor. The addition of molybdenum into TM5 was identified as significantly enlarging the optimal temperature range for mercury oxidation. The optimal mercury oxidation temperature of TM5 was only 200 °C, with an oxidation efficiency of 95%. However, the mercury oxidation efficiency of TM5 was lower than 60% at other temperatures. As for MnO2–MoO3/TiO2 (TM5Mo5), the mercury oxidation efficiency was above 80% at 200–350 °C. In particular at 250 °C, the mercury oxidation efficiency of TM5Mo5 was over 93%. Otherwise, the gaseous O2, which could supplement the lattice oxygen in the catalytic reaction, played an important role in the process of mercury oxidation over TM5Mo5. The results of X-ray photoelectron spectroscopy (XPS) suggested that mercury oxidized by O2 over TM5Mo5 followed the Mars–Maessen mechanism.

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 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 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.

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 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 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.

scholarly journals Catalytic hydrotreating of bio-oil and evaluation of main noxious emissions of gaseous phase

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rami Doukeh ◽  
Dorin Bombos ◽  
Mihaela Bombos ◽  
Elena-Emilia Oprescu ◽  
Gheorghe Dumitrascu ◽  
...  
Keyword(s):  
Gaseous Phase ◽  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Acid Number ◽  
Fixed Bed Reactor ◽  
Biomass Pyrolysis ◽  
Total Acid ◽  
Transportation Fuel ◽  
X Ray ◽  
Bio Oil

AbstractBio-oil produced from biomass pyrolysis has the potential to become an alternative renewable fuel. However due to the high content of oxygenated compounds is unsuitable as transportation fuel. The objective of this work is to evaluate the catalytic activity of CoMo /γ-Al2O3-HMS in the hydrotreating process of biomass pyrolysis bio-oil. The prepared catalyst was characterized by different techniques (X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS)) analysis. The experiments were carried out in a flow fixed-bed reactor at the temperature range of 250–320 °C, pressure between 20–40 bar, and LHSV of 3 h-1. The results showed that at mild conditions of 320 °C and 40 bar, the catalyst is very active in the hydrotreating process leading to a decrease of total acid number of hydrotreated bio-oil with almost 89% and bio-oil conversion of 87.23%. In addition, in order to evaluate the harmful emissions resulted from combustion of gaseous phase obtained in the hydrotreating process a chemical modelling algorithm was developed.

Characteristics and Regeneration Properties of Manganese Oxide Sorbent under O2 Atmosphere

2016 ◽  
Vol 859 ◽  
pp. 134-139
Author(s):  
Li Ping Liu ◽  
Shang Guan Ju ◽  
Hui Qing Wang ◽  
Xiao Wei Zhao ◽  
Jie Mi
Keyword(s):  
Manganese Oxide ◽  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Conversion Ratio ◽  
Manganese Sulfate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Different Temperatures ◽  
Xrd Techniques ◽  
Micro Reactor

The regeneration behavior of manganese oxide sorbent under O2atmosphere was investigated in a fixed bed micro-reactor under the influence of different temperatures and O2 concentrations. The change in phase of the sulfided and the regenerated sorbents was analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques. MnS, Mn3O4 and MnSO4 were found in regenerated sorbent at 400 °C, which indicated that the regeneration of the sulfided sorbent was not complete, however, MnS was converted to Mn3O4, Mn2O3 and few MnSO4 at 800 °C. The manganese sulfate formed during the regeneration but decomposed to Mn2O3 at 800 °C. MnS reacts with O2 to form Mn3O4 and MnSO4, and then MnSO4 was decomposed at 800 °C. The results show that the optimum regeneration temperature and O2 concentration obtained from this experiment are 800 °C and 2.2 vol %, respectively, and the regeneration conversion ratio was about 95%.

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 Effect of Operating Temperature, Pressure and Potassium Loading on the Performance of Silica-Supported Cobalt Catalyst in CO2 Hydrogenation to Hydrocarbon Fuel

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 807 ◽  
Author(s):  
Iloy ◽  
Jalama
Keyword(s):  
Photoelectron Spectroscopy ◽  
Operating Temperature ◽  
Fixed Bed ◽  
Co2 Hydrogenation ◽  
Fixed Bed Reactor ◽  
Activation Process ◽  
Operating Pressure ◽  
Impregnation Method ◽  
X Ray ◽  
Temperature Programmed

Potassium (1–5 wt.%)-promoted and unpromoted Co/SiO2 catalysts were prepared by impregnation method and characterized by nitrogen physisorption, temperature-programmed reduction (TPR), CO2 temperature-programmed desorption (TPD), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. They were evaluated for CO2 hydrogenation in a fixed bed reactor from 180 to 300 °C within a pressure range of 1–20 bar. The yield for hydrocarbon products other than methane (C2+) was found to increase with an increase in the operating temperature and went through a maximum of approximately 270 °C. It did not show any significant dependency on the operating pressure and decreased at potassium loadings beyond 1 wt.%. Potassium was found to enhance the catalyst ability to adsorb CO2, but limited the reduction of cobalt species during the activation process. The improved CO2 adsorption resulted in a decrease in surface H/C ratio, the latter of which enhanced the formation of C2+ hydrocarbons. The highest C2+ yield was obtained on the catalyst promoted with 1 wt.% of potassium and operated at an optimal temperature of 270 °C and a pressure of 1 bar.

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