scholarly journals Catalytic Performance of Metal Oxides Promoted Nickel Catalysts Supported on Mesoporous γ-Alumina in Dry Reforming of Methane

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 522
Author(s):  
Anis H. Fakeeha ◽  
Abdulaziz A. Bagabas ◽  
Mahmud S. Lanre ◽  
Ahmed I. Osman ◽  
Samsudeen O. Kasim ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Nickel Catalysts ◽  
Catalytic Performance ◽  
Dry Reforming ◽  
Coke Deposition ◽  
Dry Reforming Of Methane ◽  
Catalyst Stability ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Ni Catalysts

Dry reforming of CH4 was conducted over promoted Ni catalysts, supported on mesoporous gamma-alumina. The Ni catalysts were promoted by various metal oxides (CuO, ZnO, Ga2O3, or Gd2O3) and were synthesized by the incipient wetness impregnation method. The influence of the promoters on the catalyst stability, coke deposition, and H2/CO mole ratio was investigated. Stability tests were carried out for 460 min. The H2 yield was 87% over 5Ni+1Gd/Al, while the CH4 and CO2 conversions were found to decrease in the following order: 5Ni+1Gd/Al > 5Ni+1Ga/Al > 5Ni+1Zn/Al > 5Ni/Al > 5Ni+1Cu/Al. The high catalytic performance of 5Ni+1Gd/Al, 5Ni+1Ga/Al, and 5Ni+1Zn/Al was found to be closely related to their contents of NiO species, which interacted moderately and strongly with the support, whereas free NiO in 5Ni+1Cu/Al made it catalytically inactive, even than 5Ni/Al. The 5Ni+1Gd/Al catalyst showed the highest CH4 conversion of 83% with H2/CO mole ratio of ~1.0.

scholarly journals Performance Analysis of TiO2-Modified Co/MgAl2O4 Catalyst for Dry Reforming of Methane in a Fixed Bed Reactor for Syngas (H2, CO) Production

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3347
Author(s):  
Arslan Mazhar ◽  
Asif Hussain Khoja ◽  
Abul Kalam Azad ◽  
Faisal Mushtaq ◽  
Salman Raza Naqvi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Fixed Bed ◽  
Catalytic Performance ◽  
Dry Reforming ◽  
Fixed Bed Reactor ◽  
Dry Reforming Of Methane ◽  
Catalyst Stability ◽  
Feed Ratio ◽  
Catalyst Loading ◽  
Impregnation Method

Co/TiO2–MgAl2O4 was investigated in a fixed bed reactor for the dry reforming of methane (DRM) process. Co/TiO2–MgAl2O4 was prepared by modified co-precipitation, followed by the hydrothermal method. The active metal Co was loaded via the wetness impregnation method. The prepared catalyst was characterized by XRD, SEM, TGA, and FTIR. The performance of Co/TiO2–MgAl2O4 for the DRM process was investigated in a reactor with a temperature of 750 °C, a feed ratio (CO2/CH4) of 1, a catalyst loading of 0.5 g, and a feed flow rate of 20 mL min−1. The effect of support interaction with metal and the composite were studied for catalytic activity, the composite showing significantly improved results. Moreover, among the tested Co loadings, 5 wt% Co over the TiO2–MgAl2O4 composite shows the best catalytic performance. The 5%Co/TiO2–MgAl2O4 improved the CH4 and CO2 conversion by up to 70% and 80%, respectively, while the selectivity of H2 and CO improved to 43% and 46.5%, respectively. The achieved H2/CO ratio of 0.9 was due to the excess amount of CO produced because of the higher conversion rate of CO2 and the surface carbon reaction with oxygen species. Furthermore, in a time on stream (TOS) test, the catalyst exhibited 75 h of stability with significant catalytic activity. Catalyst potential lies in catalyst stability and performance results, thus encouraging the further investigation and use of the catalyst for the long-run DRM process.

scholarly journals Role of Mixed Oxides in Hydrogen Production through the Dry Reforming of Methane over Nickel Catalysts Supported on Modified γ-Al2O3

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 157
Author(s):  
Ahmed Sadeq Al-Fatesh ◽  
Mayankkumar Lakshmanbhai Chaudhary ◽  
Anis Hamza Fakeeha ◽  
Ahmed Aidid Ibrahim ◽  
Fahad Al-Mubaddel ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Nickel Catalysts ◽  
H2 Production ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Incipient Wetness Impregnation ◽  
Thermally Stable ◽  
Oxide Systems ◽  
Catalyst Systems ◽  
H2 Yield

H2 production through dry reforming of methane (DRM) is a hot topic amidst growing environmental and atom-economy concerns. Loading Ni-based reducible mixed oxide systems onto a thermally stable support is a reliable approach for obtaining catalysts of good dispersion and high stability. Herein, NiO was dispersed over MOx-modified-γ-Al2O3 (M = Ti, Mo, Si, or W; x = 2 or 3) through incipient wetness impregnation followed by calcination. The obtained catalyst systems were characterized by infrared, ultraviolet–visible, and X-ray photoelectron spectroscopies, and H2 temperature-programmed reduction. The mentioned synthetic procedure afforded the proper nucleation of different NiO-containing mixed oxides and/or interacting-NiO species. With different modifiers, the interaction of NiO with the γ-Al2O3 support was found to change, the Ni2+ environment was reformed exclusively, and the tendency of NiO species to undergo reduction was modified greatly. Catalyst systems 5Ni3MAl (M = Si, W) comprised a variety of species, whereby NiO interacted with the modifier and the support (e.g., NiSiO3, NiAl2O4, and NiWO3). These two catalyst systems displayed equal efficiency, >70% H2 yield at 800 °C, and were thermally stable for up to 420 min on stream. 5Ni3SiAl catalyst regained nearly all its activity during regeneration for up to two cycles.

scholarly journals Mechanistic Insights for Dry Reforming of Methane on Cu/Ni Bimetallic Catalysts: DFT-Assisted Microkinetic Analysis for Coke Resistance

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1043
Author(s):  
Ahmed Omran ◽  
Sun Hee Yoon ◽  
Murtaza Khan ◽  
Minhaj Ghouri ◽  
Anjaneyulu Chatla ◽  
...  
Keyword(s):  
Energy Barrier ◽  
Density Functional ◽  
Carbon Deposition ◽  
Bimetallic Catalyst ◽  
Dry Reforming ◽  
Coke Deposition ◽  
Dry Reforming Of Methane ◽  
Catalyst Stability ◽  
Effect Of Temperature ◽  
Elimination Mechanism

Density functional theory (DFT) calculations have been utilized to evaluate the complete reaction mechanism of methane dry reforming (DRM) over Ni2Cu (111) bimetallic catalyst. The detailed catalytic cycle on Ni2Cu (111) catalyst demonstrated superior coke resistance compared to pure Ni (111) and Ni2Fe (111) reported in the literature. Doping Cu in the Ni–Ni network enhanced the competitive CH oxidation by both atomic O and OH species with the latter having only 0.02 eV higher than the 1.06 eV energy barrier required for CH oxidation by atomic O. Among the C/CH oxidation pathways, C* + O* → CO (g) was the most favorable with an energy barrier of 0.72 eV. This was almost half of the energy barrier required for the rate-limiting step of CH decomposition (1.40 eV) and indicated enhanced coke deposition removal. Finally, we investigated the effect of temperature (800~1000 K) on the carbon deposition and elimination mechanism over Ni2Cu (111) catalyst. Under those realistic DRM conditions, the calculations showed a periodic cycle of simultaneous carbon deposition and elimination resulting in improved catalyst stability.

scholarly journals Advantages of Yolk Shell Catalysts for the DRM: A Comparison of Ni/ZnO@SiO2 vs. Ni/CeO2 and Ni/Al2O3

Chemistry ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Cameron Price ◽  
Emily Earles ◽  
Laura Pastor-Pérez ◽  
Jian Liu ◽  
Tomas Reina
Keyword(s):  
Supported Catalysts ◽  
Catalytic Performance ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Carbon Formation ◽  
Ni Catalysts ◽  
Carbonaceous Deposits ◽  
Different Temperatures ◽  
Encapsulation Process ◽  
Co2 Recycling

Encapsulation of metal nanoparticles is a leading technique used to inhibit the main deactivation mechanisms in dry reforming of methane reaction (DRM): Carbon formation and Sintering. Ni catalysts (15%) supported on alumina (Al2O3) and ceria (CeO2) have shown they are no exception to this analysis. The alumina supported catalysts experienced graphitic carbonaceous deposits, whilst the ceria showed considerable sintering over 15 h of DRM reaction. The effect of encapsulation compared to that of the performance of uncoated catalysts for DRM reaction has been examined at different temperatures, before conducting longer stability tests. The encapsulation of Ni/ZnO cores in silica (SiO2) leads to advantageous conversion of both CO2 and CH4 at high temperatures compared to its uncoated alternatives. This work showcases the significance of the encapsulation process and its overall effects on the catalytic performance in chemical CO2 recycling via DRM.

scholarly journals Preparation and Characterization of Ni/ZrTiAlOx Catalyst via Sol-Gel and Impregnation Methods for Low Temperature Dry Reforming of Methane

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1335
Author(s):  
Seol A Shin ◽  
Ali Alizadeh Eslami ◽  
Young Su Noh ◽  
Hyun-tae Song ◽  
Hyun Dong Kim ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Low Temperature ◽  
Sol Gel ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Incipient Wetness Impregnation ◽  
Impregnation Method ◽  
Ternary Metal ◽  
Inhibition Property ◽  
Diffuse Reflectance Infrared

Recently, the dry reforming of methane (DRM) has received much attention as a conversion technology of greenhouse gases. Ni-based catalysts supported on ternary metal oxide composite (ZrTiAlOx) were prepared to improve the coke resistance properties in the DRM (CH4:CO2 = 1) at low temperature. The ZrTiAlOx supports with different ratios of Zr/Ti were prepared through the modified Pechini sol-gel method, and then the Ni was impregnated on the synthesized support via the incipient wetness impregnation method. Considering the Zr/Ti ratios, different catalytic activity and durability in the DRM were identified. The Ni/ZrTiAlOx catalyst with Zr/Ti of 2 exhibited enhanced coke inhibition property compared to the others at low temperature DRM for 50 h. The catalysts with a high Zr/Ti ratio under the same condition were rapidly deactivated, while the catalyst with a low Zr/Ti ratio showed deficient activity. It was found from temperature-programmed surface reactions (TPSR) and DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) analysis that the addition of Ti has led in to higher catalytic stability at Zr/Ti = 2, which could be as a result of oxygen vacancies generated by the ternary metal oxides. Ni/ZrTiAlOx catalyst with ratio of Zr/Ti = 2 showed high stability and good catalytic activity towards DRM for the production of syngas.

scholarly journals Novel Ni/Ce(Ti)ZrO2 Catalysts for Methane Dry Reforming Prepared in Supercritical Alcohol Media

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3365
Author(s):  
Yuliya Bespalko ◽  
Ekaterina Smal ◽  
Mikhail Simonov ◽  
Konstantin Valeev ◽  
Valeria Fedorova ◽  
...  
Keyword(s):  
Pechini Method ◽  
Nickel Catalysts ◽  
Oxygen Storage Capacity ◽  
Dry Reforming ◽  
Oxygen Storage ◽  
Dry Reforming Of Methane ◽  
Incipient Wetness Impregnation ◽  
One Pot ◽  
Oxide Support ◽  
Supercritical Alcohol

To achieve a high activity and coking stability of nickel catalysts in dry reforming of methane, materials comprised of ceria–zirconia doped by Ti were investigated as supports. Ceria–zirconia supports doped with titanium were prepared either via the Pechini method or by synthesis in supercritical alcohol media. Ni-containing catalysts were prepared by two techniques: standard incipient wetness impregnation and one-pot synthesis. The catalytic reaction of DRM to synthesis gas was carried out in the 600–750 °C range over 5% wt. Ni/Ce(Ti)ZrO2. Dried and calcined supports and catalysts were characterized by physicochemical methods including N2 adsorption, XRD, Raman, H2-TPR, and HRTEM. Both preparation methods led to formation of solid solution with cubic fluorite-like structure, as well as after addition of Ti. Introduction of Ti should provide improved oxygen storage capacity and mobility of support oxygen. The highest activity was observed with the catalyst of 5% wt. Ni/Ce0.75Ti0.2Zr0.05O2−δ composition due to optimized oxide support structure and support oxygen mobility.

scholarly journals Impact of Small Promoter Amounts on Coke Structure in Dry Reforming over Ni/ ZrO2

2020 ◽  
Author(s):  
Robert Franz ◽  
Tobias Kuehlewind ◽  
Genrikh Shterk ◽  
Edy Abou-hamad ◽  
Alexander Parastaev ◽  
...  
Keyword(s):  
Alkali Metals ◽  
Dry Reforming ◽  
Coke Deposition ◽  
Dry Reforming Of Methane ◽  
Similar Degree ◽  
Ni Catalysts ◽  
Coke Content ◽  
K Promotion ◽  
Carbonate Species ◽  
Supported Ni

Coke deposition is one of the main challenges in the commercialization of dry reforming of methane over supported Ni catalysts. Besides the coke quantity, the structure of the deposits is also essential for the catalyst lifetime. Accordingly, in this study, we analysed the effect of different metal promoters on both these variables over Ni/ ZrO<sub>2</sub> catalysts. Alkali metals are known to block the most active coke forming sites already at low loading, leading to an investigation of Na, K and Cs. To analyse the possible contributions of coke gasification activity of the alkali metals, Mn was additionally used as a comparison. While the conversion is barely affected by the type of promoter, it has profound effect on the amount and the composition of carbon deposits formed during reaction: Addition of K or Mn reduces the coke content to a similar degree but with less carbon fibres observed in the case of K. Promotion by Cs and Na results in the lowest coke content, which is attributed to enhanced coke gasification via carbonate species

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