Decomposition of Methane over Iron Catalysts at the Range of Moderate Temperatures: The Influence of Structure of the Catalytic Systems and the Reaction Conditions on the Yield of Carbon and Morphology of Carbon Filaments

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

doi:10.1006/jcat.2001.3243

Cited by 313 publications

(168 citation statements)

References 25 publications

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“…Thus, the formation of α-Fe and Fe3C species may be important in the decomposition of methane under CH4/O2/CO2 conditions. These results are consistent with previous findings 15) . Figure 8(A) shows the SEM image of carbon filaments formed on Fe/Al2O3 under CH4/CO2/O2 conditions.…”

Section: Effect Of Additives On Fe/al2o3 Catalystsupporting

confidence: 94%

O2およびCO2の存在下における鉄系触媒上でのメタン分解

Murata

Inaba

Saito

et al. 2003

J. Jpn. Petrol. Inst.

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Methane decomposition was carried out using Fe/Al2O3 catalyst in the absence and presence of O2 and CO2. Even in the presence of O2 and CO2 (CH4/O2/CO2 = 80/10/5 vol ratio), the deactivation of Fe/Al2O3 catalyst at temperatures below 1100 K was caused mainly by accumulation of carbon products as well as oxidation of nonoxide iron species (α-Fe and Fe3C), as confirmed by X-ray diffraction, TG/DTA, and in-situ DRIFT-IR analyses. The stability of Fe/Al2O3 catalyst in the presence of O2 and CO2 was improved by the addition of some metals into the catalyst (M/Fe = 1/1 wt ratio). Methane conversion decreased monotonously from 95 to 79% after 6 h for Fe/Al2O3 catalyst. In contrast, the activity of Fe/Mg/Al2O3 catalyst at 973 K remained unchanged after 6 h (CH4 conversion 95%). This effect could be associated with the formation of MgFe2O4. The effectiveness of other metal additives on the catalyst stability was Ce, Y > Eu, La> Pr, none > V > Nb.

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Section: Effect Of Additives On Fe/al2o3 Catalystsupporting

confidence: 94%

O2およびCO2の存在下における鉄系触媒上でのメタン分解

Murata

Inaba

Saito

et al. 2003

J. Jpn. Petrol. Inst.

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“…From TEM observation, it is noticeable that carbons grown on this catalyst are heterogeneous in morphology and contain impurities of the amorphous carbon. This carbons can be classified into multi-walled carbon nanotubes and filamentous carbons with a chain-like structure [23,24]. The walls of the chain-like carbon fibers (CCF) are of uneven structures and the hollows of these carbon fibers are divided into many cells.…”

Section: Ni/caco 3 Catalystmentioning

confidence: 99%

Effect of the Support on Structure of the Multi-Walled Carbon Nanotubes Grown By CCVD over Nickel Nanoparticles

Lemesh¹,

Strizhak²

2017

JAN

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Abstract. Effect of the support and preparation method of the Ni/CaO and Ni/CaCO 3 impregnated catalysts on the morphology, diameters and growth mechanisms of the MWCNTs grown from ethylene by CCVD synthesis were studied. It was found that the interactions between the support and Ni nanoparticles in both cases are mainly weak and the growth mechanism of the majority of the carbon nanotubes is the "tip-growth". The structure of the nanotubes produced using different catalysts was, however, significantly different. Use of the Ni/CaO catalyst results in the formation of two types of the MWCNTs on the basis of the diameters. At the Ni/CaCO 3 , the formation of the MWCNTs and chain-like carbons fibers was observed. The differences in the morphology and diameters related to the distinct chemical transformation of the support and active phase of the catalyst during the catalyst preparation and reduction, as well as during synthesis of the nanotubes.

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“…The history of carbon nanofibers (CNFs) can be traced back to 1889 when the method for synthesis of filamentous carbon by hydrolysis of a mixture of methane and hydrogen in an iron crucible was reported (Ermakova et al, 2001). Carbon nanofibers (CNFs) have unique chemical stability, electrical conductivity, mechanical strength and textural/surface properties (De Jong and Geus, 2000), which make them good candidates for absorbents and catalysts and therefore are the subject of numerous studies especially in the latest few decades.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Vapor Decomposition of Methane over Nickle Catalyst: Growth Rate and the Corresponding Microstructures of Carbon Nanofibers

Sui

Sun

Zhou

et al. 2009

J. Chem. Eng. Japan

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Time-resolved intrinsic reaction rate of catalytic vapor deposition of methane into carbon nanofibers (CNFs) and hydrogen on supported Ni catalysts was determined under different reaction temperatures (773-973 K) and feed compositions (P H 2 = 0 P H 2 = 0 P H 2 = 0-0.29 atm, P CH 4 = 0.28 P CH 4 = 0.28 P CH 4 = 0.28-0.71 atm) and the microstructure of the produced CNFs was characterized by Raman and TEM. The results showed that, increasing the reaction temperature, methane partial pressure and decreasing hydrogen partial pressure increased the initial reaction rate but generally led to fast catalyst deactivation. A high carbon yield per unit catalyst was obtained as a compromise between initial reaction rate and catalyst deactivation rate. The microstructures of the produced CNFs had a close relationship with the initial reaction rate. The CNFs produced with high initial rate tended to have a small angle between the graphene layers and the growth axis, thin diameter and a hollow core. This phenomenon can be used for monitoring and controlling the CNFs synthesis process.

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Decomposition of Methane over Iron Catalysts at the Range of Moderate Temperatures: The Influence of Structure of the Catalytic Systems and the Reaction Conditions on the Yield of Carbon and Morphology of Carbon Filaments

Cited by 313 publications

References 25 publications

O<SUB>2</SUB>およびCO<SUB>2</SUB>の存在下における鉄系触媒上でのメタン分解

O<SUB>2</SUB>およびCO<SUB>2</SUB>の存在下における鉄系触媒上でのメタン分解

Effect of the Support on Structure of the Multi-Walled Carbon Nanotubes Grown By CCVD over Nickel Nanoparticles

Catalytic Vapor Decomposition of Methane over Nickle Catalyst: Growth Rate and the Corresponding Microstructures of Carbon Nanofibers

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