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Zhang, Xunli; Hayward, D.; Mingos, D. Michael P.

doi:10.1023/a:1021069510797

Cited by 42 publications

(17 citation statements)

References 22 publications

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“…Studies of the oscillatory behaviour over Ni and Co catalysts revealed that bare chromel-alumel thermocouples could be effective catalysts for methane oxidation, being able to generate oscillatory behaviour in the temperature range from 650 to 730°C [3,8]. When using a thermocouple, precautions were taken to avoid ethane oxidation at its surface.…”

Section: Methodsmentioning

confidence: 99%

“…The size of the first sample (Co1) was 7 · 3 · 0.75 mm 3 and the size of the second sample (Co2) was 4 · 4 · 0.16 mm 3 . Temperature of Co1 sample was measured by a chromel-alumel thermocouple in a stainless steel shell welded to the sample.…”

Section: Methodsmentioning

confidence: 99%

“…The study of these phenomena is one of the most exciting fields in heterogeneous catalysis and more than 65 oscillating heterogeneous catalytic systems are known today [1]. Recently an oscillatory behaviour during methane oxidation has been discovered and investigated over Ni [2][3][4][5][6] and Co catalysts [7,8]. It was suggested that the oscillatory behaviour during methane oxidation over nickel and cobalt catalysts originated from the periodic oxidation and reduction of the metal catalyst [9].…”

Section: Introductionmentioning

confidence: 99%

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Oscillatory Behaviour During Ethane Oxidation Over Nickel and Cobalt Catalysts

et al. 2007

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Oscillatory behaviour during ethane oxidation over a nickel foil and a cobalt foil has been studied using on-line mass-spectrometry and video recording of the catalyst surface colour. It was demonstrated that during the oscillatory behaviour, periodic transitions of the catalyst surface from an oxidised state to a reduced state occurred together with a variation of the catalyst temperature. Simultaneous measurements of gas phase concentrations revealed that mostly CO 2 was produced over the oxidised state, while CO and H 2 production rates reached their maxima over the completely reduced surface. The comparison of the observed oscillations with known oscillations during methane oxidation over nickel and cobalt foils has been done. It was shown that the higher reducing ability of ethane was the reason of an increase of the frequency of the oscillations over both catalysts and a significant decrease of the temperature range of the oscillations over the cobalt foil.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Oscillatory Behaviour During Ethane Oxidation Over Nickel and Cobalt Catalysts

et al. 2007

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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: 98%

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

et al. 2012

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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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Cited by 42 publications

References 22 publications

Oscillatory Behaviour During Ethane Oxidation Over Nickel and Cobalt Catalysts

Oscillatory Behaviour During Ethane Oxidation Over Nickel and Cobalt Catalysts

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

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

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