Oscillatory Behaviour During Ethane Oxidation Over Nickel and Cobalt Catalysts

Bychkov, V. Yu.; Tyulenin, Yu. P.; Slinko, M. M.; Корчак, В. Н.

doi:10.1007/s10562-007-9241-3

Cited by 20 publications

(7 citation statements)

References 12 publications

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“…The oscil lations of the product and reactant concentrations were accompanied by the periodic oxidation-reduc tion of the catalyst surface and by oscillations of the catalyst temperature. Similar self oscillations were observed in the oxidation of ethane [10] and propane [11][12][13] on nickel.…”

Section: Introductionsupporting

confidence: 75%

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

et al. 2012

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Section: Introductionsupporting

confidence: 75%

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

et al. 2012

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“…It should be noted that the self-sustained oscillations of the relaxation type were detected in the oxidation of methane under oxygen-deficient conditions at atmospheric pressure on a variety of catalysts, including Ni wires, foils, and foams, Ni/Cr alloys, Co foils, Pd films and foils, as well as supported Ni-, Pd-, Rh-, and Ru-based catalysts. ,,− The oscillations were detected of both product and reactant concentrations and the catalyst temperature. Similar oscillations were also observed in the oxidation of ethane and propane over Ni wires and foils. ,,− All of these observations point out that the same oscillatory mechanism is realized in the oxidation of light hydrocarbons.…”

Section: Introductionsupporting

confidence: 67%

Experimental Study and Mathematical Modeling of Self-Sustained Kinetic Oscillations in Catalytic Oxidation of Methane over Nickel

et al. 2017

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The self-sustained kinetic oscillations in the oxidation of CH over Ni foil have been studied at atmospheric pressure using an X-ray diffraction technique and mass spectrometry. It has been shown that the regular oscillations appear under oxygen-deficient conditions; CO, CO, H, and HO are detected as the products. According to in situ X-ray diffraction measurements, nickel periodically oxidizes to NiO initiating the reaction-rate oscillations. To describe the oscillations, we have proposed a five-stage mechanism of the partial oxidation of methane over Ni and a corresponding three-variable kinetic model. The mechanism considers catalytic methane decomposition, dissociative adsorption of oxygen, transformation of chemisorbed oxygen to surface nickel oxide, and reaction of adsorbed carbon and oxygen species to form CO. Analysis of the kinetic model indicates that the competition of two processes, i.e., the oxidation and the carbonization of the catalyst surface, is the driving force of the self-sustained oscillations in the oxidation of methane. We have compared this mechanism with the detailed 18-stage mechanism described previously by Lashina et al. (Kinetics and Catalysis 2012, 53, 374-383). It has been shown that both kinetic mechanisms coupled with a continuous stirred-tank reactor model describe well the oscillatory behavior in the oxidation of methane under non-isothermal conditions.

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“…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%

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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Oscillatory Behaviour During Ethane Oxidation Over Nickel and Cobalt Catalysts

Cited by 20 publications

References 12 publications

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

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

Experimental Study and Mathematical Modeling of Self-Sustained Kinetic Oscillations in Catalytic Oxidation of Methane over Nickel

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

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