Carbon dioxide hydrogenation on potassium-promoted nickel catalysts

Campbell, T.K.; Falconer, John L.

doi:10.1016/s0166-9834(00)80835-0

Cited by 44 publications

(19 citation statements)

References 16 publications

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“…The activation energies ( E a ) were determined from the slope of the Arrhenius plot and reported in Table . These values are consistent, even slightly lower, with respect to those presented in the existing literature for Ni‐based catalysts …”

Section: Resultssupporting

confidence: 90%

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Enhanced Catalytic Activity of Iron‐Promoted Nickel on γ‐Al₂O₃ Nanosheets for Carbon Dioxide Methanation

et al. 2018

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Iron‐promoted nickel on γ‐Al2O3 nanosheets shows enhanced catalytic activity, selectivity, and stability for carbon dioxide methanation, a relevant process for energy storage and transportation (power‐to‐gas) for the future low‐carbon economy. Nanosheet‐type catalysts were synthesized by a two‐step hydrothermal method and characterized by several physicochemical methods. The catalytic activity for CO2 methanation was investigated in the 300–350 °C temperature range at a pressure of 5 bar. A high activity at 300 °C (≈860 molCH4 molNi−1 h−1) and 99 % CH4 selectivity with a stable catalytic performance for more than 50 h were observed for the nanosheets‐based sample promoted with iron. With respect to a commercial methanation catalyst, the Fe‐promoted nanosheets‐based catalyst showed an integral rate of CO2 conversion to methane more than three times higher, with a rate of deactivation 5 times lower at 300 °C. With respect to nanosheets catalysts without the use of Fe as promoter, the rate of CO2 conversion is approximately 5 times higher, and with respect to a catalyst with the same composition, but prepared using a bulk‐type alumina, the activity is approximately 2.5 times higher. There is thus a synergistic role of the unique nanostructure and Fe promotion. The nanosheets structure promotes Ni dispersion, forming small Ni nanoparticles (≈11–13 nm) upon reduction, which are very stable with time on stream and against oxidation. Fe forms an alloy with Ni upon reduction and improves the dispersion and reduction degree. No relation is observed between the quantitative number of basic sites and turnover frequency (TOF) values, but data suggest that the mobility of adsorbed CO2 towards the Ni particles, favored by the weakening of medium‐strong basic sites related to Fe promotion and nanosheets structure, determines the reaction rate and TOF.

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Section: Resultssupporting

confidence: 90%

“…These valuesa re consistent, even slightly lower, with respecttot hose presentedint he existing literature for Ni-based catalysts. [52][53][54]…”

Section: Resultsmentioning

confidence: 99%

Enhanced Catalytic Activity of Iron‐Promoted Nickel on γ‐Al₂O₃ Nanosheets for Carbon Dioxide Methanation

et al. 2018

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“…The major difference between the catalytic performance under steady-and unsteady-state operation is the function of K where selectivity to CO was notably increased under steady-state conditions (43 and 24% CO selectivity at 250 and 350 °C, respectively), while this was not the case under unsteady-state conditions where high selectivity (>90%) to CH4 was achieved for NKZ. The steady-state selectivity characteristics are in agreement with the previous findings where potassium enhances CO selectivity of Ni catalysts by lowering the activation energy for CO formation [18,19]. This indicates that the catalytic properties can be largely altered and the distinct reactivity can arise by the unsteady-state operation.…”

Section: Ccr Performance Of Unpromoted and K-or La-promoted Ni/zro2 Csupporting

confidence: 90%

Continuous CO2 capture and reduction in one process: CO2 methanation over unpromoted and promoted Ni/ZrO2

Urakawa

2018

Journal of CO2 Utilization

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The recently demonstrated concept to combine CO2 capture and utilization in one process using isothermal unsteady-state operation, namely CO2 capture and reduction (CCR), was applied for the first time to CO2 methanation using unpromoted and K-or La-promoted Ni/ZrO2 catalysts. Both K and La promoters significantly improve CO2 capture capacity and also CO2 conversion selectivity to methane. The K-promoted catalyst (Ni-K/ZrO2) captures a larger amount of CO2 at high temperature but the capture capacity drops at low temperature due to incomplete catalyst regeneration during the cyclic unsteady-state reaction condition. In contrast, the La-promoted catalyst (Ni-La/ZrO2) shows temperatureindependent CO2 capture capacity and rapid reduction of captured CO2, thus leading to stable CCR performance. The nature of the active sites and mechanistic details were gained by TPR, reductive CO2-TPD and space-and time-resolved operando DRIFTS, holistically elucidating the effects of the promoters and their impacts on CCR activity.

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“…A significant decrease of the specific activity of the methanation of CO, i.e. the reverse of the steam-reforming reaction, due to the addition of alkali metal ions has been reported frequently [45][46][47][48]. The decrease of specific activity has been ascribed to electron donation from the alkali metal species to the nickel, thereby influencing the rates of the surface processes and/or the adsorption equilibria and/or the adsorption kinetics [29,31,32,49,50].…”

Section: Discussionmentioning

confidence: 99%

Nickel catalysts for internal reforming in molten carbonate fuel cells

Berger

Doesburg

Ommen

et al. 1996

Applied Catalysis A: General

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Natural gas may be used instead of hydrogen as fuel for the molten carbonate fuel cell (MCFC) by steam reforming the natural gas inside the MCFC, using a nickel catalyst (internal reforming). The severe conditions inside the MCFC, however, require that the catalyst has a very high stability. In order to find suitable types of nickel catalysts and to obtain more knowledge about the deactivation mechanism(s) occurring during internal reforming, a series of nickel catalysts was prepared and subjected to stability tests at 973 K in an atmosphere containing steam and lithium and potassium hydroxide vapours. All the catalysts prepared showed a significant growth of the nickel crystallites during the test, especially one based on c~-Al203 and a coprecipitated Ni/AI20 3 sample having a very high nickel content. However, this growth of nickel crystallites only partially explained the very strong deactivation observed in most cases. Only a coprecipitated nickel/alumina catalyst with high alumina content and a deposition-precipitation catalyst showed satisfactory residual activities. Addition of magnesium or lanthanum oxide to a coprecipitated nickel/alumina catalyst decreased the stability.Adsorption and retention of the alkali was the most important factor determining the stability of a catalyst in an atmosphere containing alkali hydroxides. This is because the catalyst bed may remain active if a small part of the catalyst bed retains all the alkali.

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Carbon dioxide hydrogenation on potassium-promoted nickel catalysts

Cited by 44 publications

References 16 publications

Enhanced Catalytic Activity of Iron‐Promoted Nickel on γ‐Al₂O₃ Nanosheets for Carbon Dioxide Methanation

Enhanced Catalytic Activity of Iron‐Promoted Nickel on γ‐Al₂O₃ Nanosheets for Carbon Dioxide Methanation

Continuous CO2 capture and reduction in one process: CO2 methanation over unpromoted and promoted Ni/ZrO2

Nickel catalysts for internal reforming in molten carbonate fuel cells

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Carbon dioxide hydrogenation on potassium-promoted nickel catalysts

Cited by 44 publications

References 16 publications

Enhanced Catalytic Activity of Iron‐Promoted Nickel on γ‐Al2O3 Nanosheets for Carbon Dioxide Methanation

Enhanced Catalytic Activity of Iron‐Promoted Nickel on γ‐Al2O3 Nanosheets for Carbon Dioxide Methanation

Continuous CO2 capture and reduction in one process: CO2 methanation over unpromoted and promoted Ni/ZrO2

Nickel catalysts for internal reforming in molten carbonate fuel cells

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Enhanced Catalytic Activity of Iron‐Promoted Nickel on γ‐Al₂O₃ Nanosheets for Carbon Dioxide Methanation

Enhanced Catalytic Activity of Iron‐Promoted Nickel on γ‐Al₂O₃ Nanosheets for Carbon Dioxide Methanation