scholarly journals A Decrease in NiO-MgO Phase Through Its Solid Solution Equilibrium with Tetragonal(La1−zSrz)2Ni1−yMgyO4−δ: Effect on Catalytic Partial Oxidation of Methane

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Xiong Yin ◽  
Liang Hong ◽  
Zhengliang Gong
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Partial Oxidation ◽  
Methane Conversion ◽  
Partial Oxidation Of Methane ◽  
Catalytic Partial Oxidation ◽  
X Ray Diffraction ◽  
Oxide Mixture ◽  
X Ray ◽  
Oxidation Of Methane

Calcination of an oxide mixture consisting of 0.4 La2O3, 0.2 SrCO3,(1−x)NiO, andxMgO at800∘Cresults in an equilibrium between tetragonal(La1−zSrz)2Ni1−yMgyO4−δphase and NiO-MgO phase. Forming rock-salt NiO-MgO facilitates the NiO to join the tetragonal phase. The size of the NiO-MgO phase in the resulting composite is reduced with the increase in MgO (thexvalue). The composite thus obtained is used to catalyze partial oxidation of methane, and the maximum methane conversion of ca. 93% is achieved whenx=0.2. A further rise inxvalue results in a monotonic decrease in the methane conversion. X-ray diffraction, electron microscopy, and chemosorption all confirm a decrease in both size and amount of the supportedNi0clusters with the increase in MgO dosage. The reduction in size promotes the dispersion ofNi0sites and gives rise to both high activity and strong coking resistance.

scholarly journals Catalytic Performance of Calcium-Lanthanum co-doped Ceria (Ce0.85-xLa0.15CaxO2-δ) in Partial Oxidation of Methane

2021 ◽  
Vol 16 (3) ◽  
pp. 548-554
Author(s):  
Qassam Sarmad ◽  
U. M. Khan ◽  
Mustafa Anwar ◽  
A. H. Khoja ◽  
M. Ali ◽  
...  
Keyword(s):  
Partial Oxidation ◽  
Sol Gel ◽  
Performance Testing ◽  
Combustion Method ◽  
Catalytic Performance ◽  
Partial Oxidation Of Methane ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxidation Of Methane ◽  
Gel Combustion

In this study, Ce0.85-xLa0.15CaxO2-δ was synthesized using sol-gel combustion method and appliedfor partial oxidation of methane (POM). The physicochemical properties of catalyst were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and thermogravimetric analysis (TGA). Material shows a pure cubical structure and is highly stable up to 850 °C. The performance testing indicated the conversion of CH4 is 65% and selectivity of H2 and CO are 28% and 8%, respectively. The performance indicated the catalyst has a potential to be used for partial oxidation of methane on a larger scale. 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 Multi-length scale 5D diffraction imaging of Ni–Pd/CeO2–ZrO2/Al2O3 catalyst during partial oxidation of methane

2021 ◽  
Author(s):  
Dorota Matras ◽  
Antonis Vamvakeros ◽  
Simon D. M. Jacques ◽  
Marco di Michiel ◽  
Vesna Middelkoop ◽  
...  
Keyword(s):  
Partial Oxidation ◽  
Partial Oxidation Of Methane ◽  
Length Scale ◽  
Catalytic Reactor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxidation Of Methane ◽  
Multiple Length Scales ◽  
Diffraction Imaging ◽  
Al2o3 Catalyst

Operando 5D X-ray diffraction imaging reveals complex heterogeneities across multiple length scales in a catalytic reactor for the partial oxidation of methane reaction.

scholarly journals Oscillatory Behaviour of Ni Supported on ZrO2 in the Catalytic Partial Oxidation of Methane as Determined by Activation Procedure

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2495
Author(s):  
Daniela Pietrogiacomi ◽  
Maria Cristina Campa ◽  
Ida Pettiti ◽  
Simonetta Tuti ◽  
Giulia Luccisano ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Partial Oxidation ◽  
Active Sites ◽  
Direct Reduction ◽  
Partial Oxidation Of Methane ◽  
Catalytic Partial Oxidation ◽  
Oxidation Of Methane ◽  
Short Contact Time ◽  
Oxidation Reduction ◽  
Ni Species

Ni/ZrO2 catalysts, active and selective for the catalytic partial oxidation of methane to syngas (CH4-CPO), were prepared by the dry impregnation of zirconium oxyhydroxide (Zhy) or monoclinic ZrO2 (Zm), calcination at 1173 K and activation by different procedures: oxidation-reduction (ox-red) or direct reduction (red). The characterization included XRD, FESEM, in situ FTIR and Raman spectroscopies, TPR, and specific surface area measurements. Catalytic activity experiments were carried out in a flow apparatus with a mixture of CH4:O2 = 2:1 in a short contact time. Compared to Zm, Zhy favoured the formation of smaller NiO particles, implying a higher number of Ni sites strongly interacting with the support. In all the activated Ni/ZrO2 catalysts, the Ni–ZrO2 interaction was strong enough to limit Ni aggregation during the catalytic runs. The catalytic activity depended on the activation procedures; the ox-red treatment yielded very active and stable catalysts, whereas the red treatment yielded catalysts with oscillating activity, ascribed to the formation of Niδ+ carbide-like species. The results suggested that Ni dispersion was not the main factor affecting the activity, and that active sites for CH4-CPO could be Ni species at the boundary of the metal particles in a specific configuration and nuclearity.

scholarly journals Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

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