ChemInform Abstract: MULTIPLE ISOTOPE TRACING OF METHANATION OVER NICKEL CATALYST. II. DEUTEROMETHANES TRACING

Happel, John; Cheh, H. Y.; Otarod, Masood; Ozawa, Sentaro; Severdia, A.J.; YOSHIDA, T.; FTHENAKIS, V.

doi:10.1002/chin.198237101

Cited by 7 publications

(10 citation statements)

References 1 publication

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“…35 Winslow and Bell showed the existence of two different carbon species, one being a reactive surface intermediate and the other one involved in deactivation. These two pools of carbidic carbon have also been observed by others such as Happel et al for nickel 15 and van Dijk et al for cobalt 36 albeit that, different from the work of Winslow and Bell, all of the species could be hydrogenated to methane. Van Dijk et al reported that C hydrogenation is the slow step in the mechanism of CO hydrogenation to methane by supported cobalt.…”

Section: Introductionsupporting

confidence: 68%

Mechanism of Cobalt-Catalyzed CO Hydrogenation: 1. Methanation

et al. 2017

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The mechanism of CO hydrogenation to CH4 at 260 °C on a cobalt catalyst is investigated using steady-state isotopic transient kinetic analysis (SSITKA) and backward and forward chemical transient kinetic analysis (CTKA). The dependence of CHx residence time is determined by 12CO/H2 → 13CO/H2 SSITKA as a function of the CO and H2 partial pressure and shows that the CH4 formation rate is mainly controlled by CHx hydrogenation rather than CO dissociation. Backward CO/H2 → H2 CTKA emphasizes the importance of H coverage on the slow CHx hydrogenation step. The H coverage strongly depends on the CO coverage, which is directly related to CO partial pressure. Combining SSITKA and backward CTKA allows determining that the amount of additional CH4 obtained during CTKA is nearly equal to the amount of CO adsorbed to the cobalt surface. Thus, under the given conditions overall barrier for CO hydrogenation to CH4 under methanation condition is lower than the CO adsorption energy. Forward CTKA measurements reveal that O hydrogenation to H2O is also a relatively slow step compared to CO dissociation. The combined transient kinetic data are used to fit an explicit microkinetic model for the methanation reaction. The mechanism involving direct CO dissociation represents the data better than a mechanism in which H-assisted CO dissociation is assumed. Microkinetics simulations based on the fitted parameters confirms that under methanation conditions the overall CO consumption rate is mainly controlled by C hydrogenation and to a smaller degree by O hydrogenation and CO dissociation. These simulations are also used to explore the influence of CO and H2 partial pressure on possible rate-controlling steps.

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Section: Introductionsupporting

confidence: 68%

Mechanism of Cobalt-Catalyzed CO Hydrogenation: 1. Methanation

et al. 2017

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“…Nickel catalysts are promising for the APR process because they readily cleave C-C bonds [14] and show high activity for the water-gas-shift reaction [15]. However, nickel catalysts also cleave C-O bonds, especially in the hydrogenation of CO and CO 2 (through the reverse water-gas-shift reaction) to form methane [16][17][18][19][20].…”

Section: Discussionmentioning

confidence: 99%

Aqueous-phase reforming of oxygenated hydrocarbons over Sn-modified Ni catalysts

Shabaker

Huber

Dumesic

2004

Journal of Catalysis

365

237

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“…[1][2][3][4][5][6] Tamaru and co-workers 1-3 used a C 18 O/C 16 O isotopic jump method to detect the rates of C 18 O desorption from Pd and Rh polycrystalline surfaces and found that the rate of desorption in the presence of gas-phase C 16 O is faster than in a vacuum. These authors reported that desorption rates of C 18 O were proportional to the pressure of C 16 O in the gas phase. This phenomenon was labeled "adsorption-assisted desorption".…”

Section: Introductionmentioning

confidence: 99%

Readsorption and Adsorption-Assisted Desorption of CO₂ on Basic Solids

Iglesia

1998

J. Phys. Chem. B

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The desorption of 13 CO 2 from the surface of basic oxides based on modified MgO was examined at conditions of chemical equilibrium using a 13 CO 2 / 12 CO 2 isotopic switch method. 13CO 2 desorption rates increase with increasing concentration of 12 CO 2 in the gas phase and with increasing carrier gas flow rate, both during isotopic switch and transient temperature-programmed desorption of CO 2 . These effects are caused by a decrease in the probability of 13 CO 2 readsorption and not by faster desorption steps assisted by gas-phase 12 CO 2 . This isotopic switch method allows the determination of desorption rates and of the density of sites that can bind CO 2 reversibly at conditions typical of steady-state catalytic reactions. These measurements require, however, that we include in data analysis protocols any effects of readsorption processes.

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ChemInform Abstract: MULTIPLE ISOTOPE TRACING OF METHANATION OVER NICKEL CATALYST. II. DEUTEROMETHANES TRACING

Cited by 7 publications

References 1 publication

Mechanism of Cobalt-Catalyzed CO Hydrogenation: 1. Methanation

Mechanism of Cobalt-Catalyzed CO Hydrogenation: 1. Methanation

Aqueous-phase reforming of oxygenated hydrocarbons over Sn-modified Ni catalysts

Readsorption and Adsorption-Assisted Desorption of CO₂ on Basic Solids

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ChemInform Abstract: MULTIPLE ISOTOPE TRACING OF METHANATION OVER NICKEL CATALYST. II. DEUTEROMETHANES TRACING

Cited by 7 publications

References 1 publication

Mechanism of Cobalt-Catalyzed CO Hydrogenation: 1. Methanation

Mechanism of Cobalt-Catalyzed CO Hydrogenation: 1. Methanation

Aqueous-phase reforming of oxygenated hydrocarbons over Sn-modified Ni catalysts

Readsorption and Adsorption-Assisted Desorption of CO2 on Basic Solids

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Readsorption and Adsorption-Assisted Desorption of CO₂ on Basic Solids