Oscillatory behaviour during the partial oxidation of methane over cobalt wires and foils

Zhang, Xunli; Lee, Colleen S.-M; Mingos, D. Michael P.; Hayward, D.

doi:10.1016/s0926-860x(03)00154-6

Cited by 48 publications

(14 citation statements)

References 14 publications

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“…Deng et al also reported that adding small amounts of ceria to the oxide support could help stabilise the oscillations. Other works by Zhang et al [17,18] concluded that oscillations may also be observed when using metallic nickel or cobalt foils. However, their intensities and frequencies were lower than what had been observed with palladium [16].…”

Section: Introductionmentioning

confidence: 95%

Oscillatory Behavior of Pd-Au Catalysts in Toluene Total Oxidation

et al. 2018

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In this work, the activity of bimetallic Pd-Au doped hierarchically structured titania catalysts has been investigated in the total oxidation of toluene. In earlier works, doping titania with group Vb metal oxides ensured an increased catalytic performance in the elimination of VOC molecules. A synergy between gold and palladium loaded at the surface of titania supports provided better performances in VOC oxidation reactions. Therefore, the main focus in this work was to investigate the durability of the prepared catalysts under long time-on-stream periods. Vanadium-doped catalysts showed a stable activity throughout the whole 110 h test, whereas, surprisingly, niobium-doped catalysts presented a cycle-like activity while nevertheless maintaining a high performance in toluene elimination. Operando Diffuse Reflectance Infrared Fourrier Transform spectroscopy (DRIFT) experiments revealed that variations in the presence of OH radicals and the presence of carbonaceous compounds adsorbed at the surface of spent catalysts varies with the occurrence of oscillations. X-ray Photoelectron Spectroscopy (XPS) results show that interactions between the material and the active phase provided extra amounts of mobile oxygen species and participated in easing the reduction of palladium. An enhanced redox reaction scheme is thus obtained and allows the occurrence of the cyclic-like performance of the catalyst.

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Section: Introductionmentioning

confidence: 95%

Oscillatory Behavior of Pd-Au Catalysts in Toluene Total Oxidation

et al. 2018

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“…Since cobalt is typically a good catalyst for methane partial oxidation [35,36], the acquirement of high OCV and power density was somewhat surprising. Fig.…”

Section: In Situ Reduction With Hydrogenmentioning

confidence: 99%

Initialization of a methane-fueled single-chamber solid-oxide fuel cell with NiO+SDC anode and BSCF+SDC cathode

Zhang

Zheng

Ran

et al. 2008

Journal of Power Sources

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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%

“…For instance, the oscillations in the oxidation of propane over Ni exist when the propane/oxygen molar ratio ranges from 3/1 to 15/1 [25]. Besides, strong reaction-induced changes in the catalyst morphology are observed during the oscillations [11,15,23].…”

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 the partial oxidation of methane over cobalt wires and foils

Cited by 48 publications

References 14 publications

Oscillatory Behavior of Pd-Au Catalysts in Toluene Total Oxidation

Oscillatory Behavior of Pd-Au Catalysts in Toluene Total Oxidation

Initialization of a methane-fueled single-chamber solid-oxide fuel cell with NiO+SDC anode and BSCF+SDC cathode

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

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