Effective catalysts for direct cracking of methane to produce hydrogen and filamentous carbon

Ермакова, М. А.; Ermakov, D. Yu.; Kuvshinov, G. G.

doi:10.1016/s0926-860x(00)00433-6

Cited by 238 publications

(98 citation statements)

References 26 publications

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“…For the as-prepared Ni/HAp catalyst, we observed diffraction peaks arising from different planes of the NiO phase (i.e., 2h = 37.2° (111) , suggesting sintering and aggregation of the nickel phase during the heat treatment in a hydrogen atmosphere. The strong influence of the metal particle size on the CNF yield has been previously reported [7,26,27]. Excessively small metal particles will not form CNFs because the quantity of metal is not sufficient to enable CNF formation according to the proposed mechanism of CNF growth during CCVD.…”

Section: Resultsmentioning

confidence: 83%

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Growth of carbon nanofibers from methane on a hydroxyapatite-supported nickel catalyst

et al. 2016

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Carbon nanofibers (CNFs) were grown using catalytic chemical vapor deposition (CCVD) with methane as the carbon source and a hydroxyapatite-supported nickel catalyst (Ni/HAp). The catalyst, which contained approximately 14 wt% Ni, was prepared using the incipient wetness method with an aqueous nickel nitrate solution. Temperature-programmed reduction and X-ray diffraction were used to characterize the active phase of Ni/HAp. Three variables were evaluated to optimize the CNF growth process, including the temperature and the time of catalyst reduction as well as the reaction time, at 650°C. Regardless of the applied CCVD process conditions, herringbone bamboo-like CNFs were grown during methane decomposition over Ni/HAp, which was confirmed using transmission electron microscopy. A high CNF yield of nearly 10 g CNF g cat -1was achieved at 650°C after a reaction time of 3 h when the catalyst was subjected to a reduction at the same temperature for 2 h under a hydrogen flow prior to synthesis. As the reduction temperature increased from 450 to 650°C, both the yield and diameters of the CNFs increased. The beneficial effects of including hydrogen in the reaction mixture on the catalytic performance of Ni/ HAp and the purity of the grown CNFs were demonstrated.

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Section: Resultsmentioning

confidence: 83%

“…Therefore, the synthesized Ni/ HAp catalyst with an average Ni crystallite size of 34 nm appears to be a promising catalytic system for CNF growth. Some studies [26,27] have reported that Ni particles with sizes of 10-60 nm are characteristic of highly active catalysts for the production of CNFs via methane decomposition.…”

Section: Resultsmentioning

confidence: 99%

Growth of carbon nanofibers from methane on a hydroxyapatite-supported nickel catalyst

et al. 2016

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“…In Figures 9(e) and 9(f), the filamentous carbon with a hollow structure filled in several small metal particles, suggesting that the iron species were gradually divided into smaller ones and covered by graphite layers during methane decomposition [14], causing the iron diffraction peaks (2 of 65.006 ∘ and 82.311 ∘ ) in the XRD pattern of 20Fe/MRM-after CMD to become weaker than those of 20Fe/MRM catalyst. The fragmentation of iron species followed by covering with graphite layers should deactivate the catalysts prior to CMD because the iron species cannot make contact with the methane molecules [53]. Fe 3 C forms in areas where iron species were covered with graphite, which was found in the XRD pattern (see Figure 2).…”

Section: Formation Of Carbon Depositsmentioning

confidence: 99%

Preparation of Modified Red Mud-Supported Fe Catalysts for Hydrogen Production by Catalytic Methane Decomposition

Liu

Fang

et al. 2017

Journal of Nanomaterials

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A modified red mud-(MRM-) supported Fe catalyst ( Fe/MRM) was prepared using the homogeneous precipitation method and applied to methane decomposition to produce hydrogen. The TEM and SEM-EDX results suggested that the particle sizes of the Fe/MRM catalysts were much smaller than that of raw red mud (RM), and the active metal Fe was evenly distributed over the catalyst structure. Moreover, BET results indicated that the surface areas and pore volumes of the catalysts were significantly improved, and the pore sizes of Fe/MRM were distributed from 5 to 12 nm, which is typical for a mesoporous material. The activities of those catalysts for the catalytic decomposition of methane were studied at atmospheric pressure at a moderate temperature of 650 ∘ C; the results showed that the Fe/MRM catalysts were more active than RM and MRM. The methane conversion curves of Fe/MRM catalysts exhibited similar variation tendencies (three-step) during the reaction despite different Fe contents, and the loading amount of Fe clearly affected the activity of the catalysts.

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“…This temperature is higher than that of general chemical engineering processes. Therefore Ni [2][3][4][5][6][7], Fe [8,9] and Co [10] based catalyst has been used to decompose methane at lower temperature. Venugopal et al obtained the methane conversion of 32%, decomposing methane at 600˚C under 30 wt% Ni/SiO 2 [4].…”

Section: Ch (3)mentioning

confidence: 99%

Direct Preparation of Hydrogen and Carbon Nanotubes by Microwave Plasma Decomposition of Methane over Fe/Si Activated by Biased Hydrogen Plasma

Konno¹,

Onoe²,

Takiguchi³

et al. 2013

GSC

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Methane was decomposed to hydrogen and carbon nanotubes (CNTs) by microwave plasma, using Fe/Si catalyst activated by biased (−150 V) hydrogen plasma for various treatment times. Upon exposure to biased hydrogen plasma, the catalyst surface becomes lumpy within 1 min, coheres between 5 and 10 min and forms particles after 20 min. The methane conversion increased up to 93% over the treatment time of 5 min. The hydrogen yield showed as similar tendency as the methane conversion and kept 83% at treatment time of 5 min. The treatment time up to 1 min increased the amount of deposited carbon, and after treatment time of 5 min it dropped; then again after treatment time of 20 min, it increased to reach a maximum value of 22 g c /g cat . Deposited carbon was found to be consisted of carbon nanotubes. It grew vertically on the catalyst surface and reached a maximum length of 30.7 nm after treatment time of 10 min. Multiple types of CNTs were present, and the CNT diameters decreased with increasing plasma treatment time.

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Effective catalysts for direct cracking of methane to produce hydrogen and filamentous carbon

Cited by 238 publications

References 26 publications

Growth of carbon nanofibers from methane on a hydroxyapatite-supported nickel catalyst

Growth of carbon nanofibers from methane on a hydroxyapatite-supported nickel catalyst

Preparation of Modified Red Mud-Supported Fe Catalysts for Hydrogen Production by Catalytic Methane Decomposition

Direct Preparation of Hydrogen and Carbon Nanotubes by Microwave Plasma Decomposition of Methane over Fe/Si Activated by Biased Hydrogen Plasma

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