CH4 decomposition on Co catalysts: effect of temperature, dispersion, and the presence of H2 or CO in the feed

Zhang, Yi; Smith, Kevin J.

doi:10.1016/s0920-5861(02)00251-1

Cited by 62 publications

(15 citation statements)

References 30 publications

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“…The process occurring was believed to be the oxidation of carbon, deposited on the surface during the period when only methane was present in the gas phase. This deposition could be significant in the absence of oxygen although carbon deposition could take place also in the presence of both reactants in the feed which was often observed during the partial oxidation of methane over other cobalt catalysts [15,16]. The large drop in the methane signal can be explained in terms of the displacement of methane in the flow line by the sudden surge of oxygen and the large pulse of CO and CO 2 , and does not necessarily mean that methane is consumed during the reaction.…”

Section: Cutting Oxygen Supply Off Temporarilymentioning

confidence: 97%

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

Zhang

Lee

Mingos

et al. 2003

Applied Catalysis A: General

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The oscillatory behaviour over cobalt wire and foil catalysts was examined at atmospheric pressure under various reaction temperatures and argon/methane/oxygen feed gas compositions for the partial oxidation of methane. Rough and porous oxide layers on the catalyst surface were confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The results obtained from the experimental studies indicated that the oscillatory behaviour exhibited during methane oxidation was related to the behaviour of the catalyst surface switching back and forth from the reduced state to the oxidised state. The reduction of the oxide layer followed by the almost immediate re-oxidation of the metal can be accounted for only if the oxide layer formed by oxidation is different from the oxide layer existing during reduction.

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Section: Cutting Oxygen Supply Off Temporarilymentioning

confidence: 97%

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

Zhang

Lee

Mingos

et al. 2003

Applied Catalysis A: General

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“…Perhaps the major application of cobalt-based catalysts is in the Fischer-Tropsch synthesis, since cobalt has been shown to efficiently convert syn gas (CO+H 2 ) to methane or liquid fuels [8,9,10,11]. Other applications of cobalt catalysts include partial oxidation reactions [12] and decomposition of methane to form hydrogen and carbon nanotubes or filamentous carbon [13,14]. Recently cobalt has been proposed as a very promising catalyst to replace noble metals for H 2 production by steam reforming of ethanol [15,16].…”

Section: Introductionmentioning

confidence: 99%

Methanol oxidation over model cobalt catalysts: Influence of the cobalt oxidation state on the reactivity

Zafeiratos

Dintzer

Teschner

et al. 2010

Journal of Catalysis

113

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X-ray photoelectron and absorption spectroscopies (XPS and XAS) combined with on-line mass spectrometry were applied under working catalytic conditions to investigate the methanol oxidation on cobalt. Two cobalt oxidation states (Co3O4 and CoO) were prepared and investigated as regards their influence on the catalytic activity and selectivity. In addition adsorbed species were monitored in the transition of the catalyst from the non-active to the active state. It was unequivocally shown that the surface oxidation state of cobalt is readily adapted to the oxygen chemical potential in the CH3OH/O2 reaction mixture. In particular, even in rich to oxygen mixtures the Co3O4 surface is partially reduced, while the degree of surface reduction is higher as the methanol concentration in the mixture increases. The reaction selectivity depends on the cobalt oxidation state with the more reduced samples favouring the partial oxidation of methanol to formaldehyde. In the absence of oxygen, methanol is effectively reducing cobalt to the metallic state, promoting also hydrogen and CO production. Direct evidence of methoxy and formate species adsorbed on the surface upon reaction was found by analysing the O 1s and C 1s photoelectron spectra. However, the surface coverage of those species was not proportional to the catalytic activity, indicating that in the absence of surface oxygen, these species might act also as reaction inhibitors.

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“…Transition metals, such as Fe [13,17,18], Co [19,20] and Ni [21][22][23][24][25][26], have shown high catalytic activities for the TCD of methane in different reactor tests. However, experiments show that the operating conditions and the diameter of the catalyst particle have a large influence on the catalyst life and the structural properties of the deposited carbon.…”

Section: Article In Pressmentioning

confidence: 99%

Activity of NiCuAl catalyst in methane decomposition studied using a thermobalance and the structural changes in the Ni and the deposited carbon

Pinilla

Suelves

Lázaro

et al. 2008

International Journal of Hydrogen Energy

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CH4 decomposition on Co catalysts: effect of temperature, dispersion, and the presence of H2 or CO in the feed

Cited by 62 publications

References 30 publications

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

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

Methanol oxidation over model cobalt catalysts: Influence of the cobalt oxidation state on the reactivity

Activity of NiCuAl catalyst in methane decomposition studied using a thermobalance and the structural changes in the Ni and the deposited carbon

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