Dynamic behaviour of Ni-containing catalysts during partial oxidation of methane to synthesis gas

Tulenin, Yu. P.; Sinev, M. Yu.; Savkin, V. V.; Корчак, В. Н.

doi:10.1016/j.cattod.2004.03.025

Cited by 44 publications

(12 citation statements)

References 5 publications

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“…The Ni2p 3/2 spectrum shifts to a higher binding energy, and some additional peaks appear, indicating the oxidation of nickel [25]. Certainly, the electronic configuration 3d 8 of Ni 2+ ions is responsible for such a complex shape of the spectrum. According to theoretical analysis [37,38], the formation of a hole in the 2p core level in transition metals is accompanied by a strong Coulomb repulsion with the holes in the localized 3d orbitals.…”

Section: In Situ Studymentioning

confidence: 97%

“…A wide class of these reactions is the oxidation of hydrocarbons over transition metals. For instance, self-sustained rate oscillations have been noted in the oxidation of methane, ethane, propane, and butane over supported and unsupported catalysts based on Ni, Co, Pd, Pt, Rh, and Ru [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. The distinctive features of these oscillations are their long periods, ranging from several seconds to tens of minutes, and an induction period before the appearance of the regular oscillations.…”

Section: Introductionmentioning

confidence: 99%

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Evolution of self-sustained kinetic oscillations in the catalytic oxidation of propane over a nickel foil

Каичев

Teschner

Saraev

et al. 2016

Journal of Catalysis

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The evolution of self-sustained reaction-rate oscillations in the catalytic oxidation of propane over a nickel foil has been studied in situ using X-ray photoelectron spectroscopy coupled with on line mass spectrometry and gas chromatography. Changes in the effective surface area and in the catalyst morphology under reaction conditions have been examined by scanning electron microscopy and a krypton adsorption technique. It is shown that the regular kinetic oscillations arise under oxygen-lean conditions. CO, CO 2 , H 2 , H 2 O, and propylene are detected as products.The conversion of propane oscillates in a range from 1% to 23%. During the half-periods with high activity, the main reaction pathway is the partial oxidation of propane: selectivity toward CO achieves 98%. In contrast, during the half-periods with low activity, the reaction proceeds through three competitive pathways: the partial oxidation of propane, the total oxidation of propane, and the dehydrogenation of propane to propylene. The driving force for the selfsustained kinetic oscillations is the periodic reoxidation of nickel. According to the Ni2p and O1s core-level spectra measured in situ, the high-active catalyst surface is represented by metallic nickel, whereas during the inactive half-periods the catalyst surface is covered with a thick layer of NiO. The intensity of O1s spectra follows the oscillations of O 2 in the gas phase during the oxidation of propane. It is found that during the induction period before the regular oscillations appear, a rough and porous structure develops because of strong reconstruction of the catalyst surface. The thickness of the reconstructed layer is approximately 10-20 µm. This process is accompanied with at least an 80-fold increase in the effective surface area compared with a clean, non-treated nickel foil, which undoubtedly leads to a drastic increase in the number of active sites. We believe that it is the main reason for the induction period always being  Corresponding author.E-mail address: vvk@catalysis.ru (V.V. Kaichev) 2 observed before the appearance of self-sustained oscillations in the catalytic oxidation of light hydrocarbons over catalysts with a low specific surface area (single crystals, foils, or wires).Moreover, without such reconstruction, the oscillations cannot arise due to low activity of such catalysts.

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Section: In Situ Studymentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Evolution of self-sustained kinetic oscillations in the catalytic oxidation of propane over a nickel foil

Каичев

Teschner

Saraev

et al. 2016

Journal of Catalysis

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“…The COMR reaction mechanism over the Ni/TiO 2 catalysts was found to change from an indirect mechanism (oxidized) to a direct mechanism (reduced or partially reduced) depending on the oxidation state of Ni 189. While an indirect mechanism was observed for LaNi 1− x Co x O 3 catalysts,190 direct mechanisms were reported over Ni foam,191 Ni‐Cr alloys,191 Ni/Al 2 O 3 192 and reduced Ni calcium hydroxylapatite catalysts 193. At short contact times a Ni/La 2 O 3 catalyst reacted through a direct mechanism, while the same catalyst proceeded by a combination of direct and indirect mechanisms at higher contact times 53.…”

Section: Reaction Mechanismsmentioning

confidence: 99%

Energy‐Efficient Syngas Production through Catalytic Oxy‐Methane Reforming Reactions

2008

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The considerable recent interest in the conversion of stranded methane into transportable liquids as well as fuel cell technology has provided a renewed impetus to the development of efficient processes for the generation of syngas. The production of syngas (CO/H2), a very versatile intermediate, can be the most expensive step in the conversion of methane to value-added liquid fuels. The catalytic oxy reforming of methane, which is an energy-efficient process that can produce syngas at extremely high space-time yields, is discussed in this Review. As long-term catalyst performance is crucial for the wide-scale commercialization of this process, catalyst-related studies are abundant. Correspondingly, herein, emphasis is placed on discussing the different issues related to the development of catalysts for oxy reforming. Important aspects of related processes such as catalytic oxy-steam, oxy-CO2, and oxy-steam-CO2 processes will also be discussed.

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“…As a rule, self oscillations were experimentally observed in the oxidation of methane on bulk nickel catalysts (wires, foils, etc.) under oxygen deficiency conditions [5][6][7][8][9]. The self oscillations had a relaxation character.…”

Section: Introductionmentioning

confidence: 96%

Mathematical simulation of self-oscillations in methane oxidation on nickel: An isothermal model

et al. 2012

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Dynamic behaviour of Ni-containing catalysts during partial oxidation of methane to synthesis gas

Cited by 44 publications

References 5 publications

Evolution of self-sustained kinetic oscillations in the catalytic oxidation of propane over a nickel foil

Evolution of self-sustained kinetic oscillations in the catalytic oxidation of propane over a nickel foil

Energy‐Efficient Syngas Production through Catalytic Oxy‐Methane Reforming Reactions

Mathematical simulation of self-oscillations in methane oxidation on nickel: An isothermal model

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