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

scholarly journals Impact of small promoter amounts on coke structure in dry reforming of methane 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 ◽  
Superior Performance ◽  
Dry Reforming Of Methane ◽  
Similar Degree ◽  
Promoting Effect ◽  
Coke Content ◽  
Carbonate Species ◽  
Site Blocking

Coke deposition is one of the main challenges in the commercialisation 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 Na, K, and Cs promoters on both these variables over Ni/ ZrO<sub>2</sub> catalysts. Besides blocking the most active coke-forming sites already at low loading, the promoting effect of the alkali metals is also contributed by their coke gasification activity. To evaluate the additional impact of the latter, the behaviour of alkali-doped catalysts was compared to that for Mn-doped catalysts, exclusively featuring the site-blocking promotion mechanism. While the conversion is barely affected by the type of promoter, it has a profound effect on the amount and the composition of carbon deposits formed during the reaction. Promoting with K or Mn reduces the coke content to a similar degree but with less carbon fibres observed in the case of K. The promotion by Cs and Na results in the lowest coke content. The superior performance of Cs and Na-doped Ni/ZrO<sub>2</sub> catalysts is attributed to the enhanced coke gasification via carbonate species on top of the site blocking effects.

scholarly journals Impact of small promoter amounts on coke structure in dry reforming of methane 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 ◽  
Superior Performance ◽  
Dry Reforming Of Methane ◽  
Similar Degree ◽  
Promoting Effect ◽  
Coke Content ◽  
Carbonate Species ◽  
Site Blocking

Coke deposition is one of the main challenges in the commercialisation 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 Na, K, and Cs promoters on both these variables over Ni/ ZrO<sub>2</sub> catalysts. Besides blocking the most active coke-forming sites already at low loading, the promoting effect of the alkali metals is also contributed by their coke gasification activity. To evaluate the additional impact of the latter, the behaviour of alkali-doped catalysts was compared to that for Mn-doped catalysts, exclusively featuring the site-blocking promotion mechanism. While the conversion is barely affected by the type of promoter, it has a profound effect on the amount and the composition of carbon deposits formed during the reaction. Promoting with K or Mn reduces the coke content to a similar degree but with less carbon fibres observed in the case of K. The promotion by Cs and Na results in the lowest coke content. The superior performance of Cs and Na-doped Ni/ZrO<sub>2</sub> catalysts is attributed to the enhanced coke gasification via carbonate species on top of the site blocking effects.

scholarly journals Stabilities of zeolite-supported Ni catalysts for dry reforming of methane

2013 ◽  
Vol 34 (4) ◽  
pp. 764-768 ◽  
Author(s):  
Anis H FAKEEHA ◽  
Wasim U. KHAN ◽  
Ahmed S. AL-FATESH ◽  
Ahmed E. ABASAEED
Keyword(s):  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Ni Catalysts ◽  
Supported Ni Catalysts ◽  
Supported Ni

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.

First-principles theoretical study on dry reforming of methane over perfect and boron-vacancy-containing h-BN sheet-supported Ni catalysts

2021 ◽  
Vol 23 (1) ◽  
pp. 617-627
Author(s):  
Yan Zhang ◽  
Yi-Fan Yao ◽  
Yuan-Yuan Qiao ◽  
Gui-Chang Wang
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Theoretical Study ◽  
Density Functional Theory Calculations ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Ni Catalysts ◽  
Functional Theory ◽  
Supported Ni Catalysts ◽  
Supported Ni

The entire reaction mechanism of the dry reforming of methane (DRM) as well as the competition processes over perfect and boron-vacancy-containing h-BN sheet-supported Ni-catalysts (labeled Ni2/h-BN and Ni2/h-BN-B–D) was studied by density functional theory calculations in the present work.

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