scholarly journals Dry Reforming of Methane on Cobalt Catalysts: DFT-Based Insights into Carbon Deposition Versus Removal

2021 ◽  
Author(s):  
YeeJie Wong ◽  
Harry H. Halim ◽  
N. Fazila Khairudin ◽  
Thanh Ngoc Pham ◽  
Septia E. M. Putra ◽  
...  
Keyword(s):  
Carbon Deposition ◽  
Dry Reforming ◽  
Cobalt Catalysts ◽  
Dry Reforming Of Methane

scholarly journals Effect of La2O3 as a Promoter on the Pt,Pd,Ni/MgO Catalyst in Dry Reforming of Methane Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 750 ◽  
Author(s):  
Ali M. A. Al-Najar ◽  
Faris A. J. Al-Doghachi ◽  
Ali A. A. Al-Riyahee ◽  
Yun Hin Taufiq-Yap
Keyword(s):  
Carbon Deposition ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
Bet Method ◽  
Spent Catalysts ◽  
Ft Ir ◽  
Co Precipitation ◽  
Surfactant Assisted

Pt,Pd,Ni/MgO, Pt,Pd,Ni/Mg0.97La3+0.03O, Pt,Pd,Ni/Mg0.93La3+0.07O, and Pt,Pd,Ni/Mg0.85La3+0.15O (1% of each of the Ni, Pd, and Pt) catalysts were prepared by a surfactant-assisted co-precipitation method. Samples were characterized by the XRD, XPS, XRF, FT-IR, H2-TPR, TEM, the Brunauer–Emmett–Teller (BET) method, and TGA and were tested for the dry reforming of methane (DRM). TEM and thermal gravimetric analysis (TGA) methods were used to analyze the carbon deposition on spent catalysts after 200 h at 900 °C. At a temperature of 900 °C and a 1:1 CH4:CO2 ratio, the tri-metallic Pt,Pd,Ni/Mg0.85La3+0.15O catalyst with a lanthanum promoter showed a higher conversion of CH4 (85.01%) and CO2 (98.97%) compared to the Ni,Pd,Pt/MgO catalysts in the whole temperature range. The selectivity of H2/CO decreased in the following order: Pt,Pd,Ni/Mg0.85La3+0.15O > Pt,Pd,Ni/Mg0.93La3+0.07O > Pt,Pd,Ni/Mg0.97La3+0.03O > Ni,Pd,Pt/MgO. The results indicated that among the catalysts, the Pt,Pd,Ni/Mg0.85La23+0.15O catalyst exhibited the highest activity, making it the most suitable for the dry reforming of methane reaction.

scholarly journals One-Step Synthesis of Highly Dispersed and Stable Ni Nanoparticles Confined by CeO2 on SiO2 for Dry Reforming of Methane

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5956
Author(s):  
Chengyang Zhang ◽  
Renkun Zhang ◽  
Hui Liu ◽  
Qinhong Wei ◽  
Dandan Gong ◽  
...  
Keyword(s):  
Carbon Deposition ◽  
Combustion Method ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Solution Combustion ◽  
Spatial Confinement ◽  
Oxide Interfaces ◽  
Highly Dispersed ◽  
One Step ◽  
The One

Sintering and carbon deposition are the two main ways to deactivate Ni-based catalysts during methane reforming. Herein, a stable Ni-CeO2/SiO2(CSC) catalyst was prepared by a one-step colloidal solution combustion method (CSC) and used for dry reforming of methane. In the catalyst, the small Ni particles were confined by CeO2 particles and highly dispersed on the surface of SiO2, forming a spatial confinement structure with a rich Ni-CeO2 interface in the catalyst. The Ni-CeO2/SiO2(CSC) catalyst prepared by the one-step CSC method exhibited superior activity at 700 °C during dry reforming of methane, and the performance of the catalyst was stable after 20 h of reaction with only a small amount of carbon deposition present (1.8%). Due to the spatial confinement effect, Ni was stable and less than 5 nm during reaction. The small Ni particle size and rich Ni-CeO2 interface reduced the rate of carbon deposition. This colloidal combustion method could be applied to prepare stable metal-based catalysts with rich metal–oxide interfaces for high-temperature reactions.

Production of Synthesis Gas via Dry Reforming of Methane over Co-Based Catalysts: Effect on H2/CO Ratio and Carbon Deposition

2015 ◽  
Vol 38 (8) ◽  
pp. 1397-1405 ◽  
Author(s):  
Ahmed A. Ibrahim ◽  
Muhammad Awais Naeem ◽  
Anis H. Fakeeha ◽  
Wasim Ullah Khan ◽  
Ahmed S. Al-Fatesh ◽  
...  
Keyword(s):  
Synthesis Gas ◽  
Carbon Deposition ◽  
Dry Reforming ◽  
Dry Reforming Of Methane

Dry Reforming of Methane Over Cobalt Catalysts: A Literature Review of Catalyst Development

2012 ◽  
Vol 16 (4) ◽  
pp. 183-197 ◽  
Author(s):  
Anatta Wahyu Budiman ◽  
Sang-Hoon Song ◽  
Tae-Sun Chang ◽  
Chae-Ho Shin ◽  
Myoung-Jae Choi
Keyword(s):  
Literature Review ◽  
Dry Reforming ◽  
Cobalt Catalysts ◽  
Dry Reforming Of Methane ◽  
Catalyst Development

scholarly journals Biogas Conversion to Syngas Using Advanced Ni-Promoted Pyrochlore Catalysts: Effect of the CH4/CO2 Ratio

2021 ◽  
Vol 9 ◽  
Author(s):  
Estelle le Saché ◽  
Andrea Alvarez Moreno ◽  
Tomas Ramirez Reina
Keyword(s):  
Carbon Deposition ◽  
Pyrochlore Structure ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Waste Biomass ◽  
Ni Catalysts ◽  
Biogas Upgrading ◽  
Long Term Stability ◽  
Reported Data

Biogas is defined as the mixture of CH4 and CO2 produced by the anaerobic digestion of biomass. This particular mixture can be transformed in high valuable intermediates such as syngas through a process known as dry reforming (DRM). The reaction involved is highly endothermic, and catalysts capable to endure carbon deposition and metal particle sintering are required. Ni-pyrochlore catalysts have shown outstanding results in the DRM. However, most reported data deals with CH4/CO2 stoichiometric ratios resulting is a very narrow picture of the overall biogas upgrading via DRM. Therefore, this study explores the performance of an optimized Ni-doped pyrochlore, and Ni-impregnated pyrochlore catalysts in the dry reforming of methane, under different CH4/CO2 ratios, in order to simulate various representatives waste biomass feedstocks. Long-term stability tests showed that the ratio CH4/CO2 in the feed gas stream has an important influence in the catalysts' deactivation. Ni doped pyrochlore catalyst, presents less deactivation than the Ni-impregnated pyrochlore. However, biogas mixtures with a CH4 content higher than 60%, lead to a stronger deactivation in both Ni-catalysts. These results were in agreement with the thermogravimetric analysis (TGA) of the post reacted samples that showed a very limited carbon formation when using biogas mixtures with CH4 content <60%, but CH4/CO2 ratios higher than 1.25 lead to an evident carbon deposition. TGA analysis of the post reacted Ni impregnated pyrochlore, showed the highest amount of carbon deposited, even with lower stoichiometric CH4/CO2 ratios. The later result indicates that stabilization of Ni in the pyrochlore structure is vital, in order to enhance the coke resistance of this type of catalysts.

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 Encapsulated Ni@La2O3/SiO2 Catalyst with a One-Pot Method for the Dry Reforming of Methane

Catalysts ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 38 ◽  
Author(s):  
Luhui Wang ◽  
Rong Hu ◽  
Hui Liu ◽  
Qinhong Wei ◽  
Dandan Gong ◽  
...  
Keyword(s):  
Carbon Deposition ◽  
Synthesis Method ◽  
Space Velocity ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Catalyst Characterization ◽  
Porous System ◽  
Ni Nanoparticles ◽  
Solution Combustion ◽  
One Pot

Ni nanoparticles encapsulated within La2O3 porous system (Ni@La2O3), the latter supported on SiO2 (Ni@La2O3)/SiO2), effectively inhibit carbon deposition for the dry reforming of methane. In this study, Ni@La2O3/SiO2 catalyst was prepared using a one-pot colloidal solution combustion method. Catalyst characterization demonstrates that the amorphous La2O3 layer was coated on SiO2, and small Ni nanoparticles were encapsulated within the layer of amorphous La2O3. During 50 h of dry reforming of methane at 700 °C and using a weight hourly space velocity (WHSV) of 120,000 mL gcat−1 h−1, the CH4 conversion obtained was maintained at 80%, which is near the equilibrium value, while that of impregnated Ni–La2O3/SiO2 catalyst decreased from 63% to 49%. The Ni@La2O3/SiO2 catalyst exhibited very good resistance to carbon deposition, and only 1.6 wt% carbon was formed on the Ni@La2O3/SiO2 catalyst after 50 h of reaction, far lower than that of 11.5 wt% deposited on the Ni–La2O3/SiO2 catalyst. This was mainly attributed to the encapsulated Ni nanoparticles in the amorphous La2O3 layer. In addition, after reaction at 700 °C for 80 h with a high WHSV of 600,000 mL gcat−1 h−1, the Ni@La2O3/SiO2 catalyst exhibited high CH4 conversion rate, ca. 10.10 mmol gNi−1 s−1. These findings outline a simple synthesis method to prepare supported encapsulated Ni within a metal oxide porous structure catalyst for the dry reforming of methane reaction.

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