Carbon deposition over Fe, Ni, and Co foils from CO-H2-CH4-CO2-H2O, CO-CO2, CH4-H2, and CO-H2-H2O gas mixtures: I. Morphology

Jablonski, G. A.; Geurts, F. W. A. H.; Sacco, Albert; Biederman, R.R.

doi:10.1016/0008-6223(92)90111-9

Cited by 76 publications

(50 citation statements)

References 43 publications

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“…This is important since nanofiber growth is linked to particle size [72]. In larger powders, foils and other "bulk" catalysts, the fiber size is much less than the catalyst dimensions, and this has been associated with surface breakup [10,73,74] where sections of the catalysts are lifted away with the fiber. Catalyst morphology and composition are the controlling factors in carbon deposition, then, and their evolution during processing is critical to the deposition process.…”

Section: Processing Considerationsmentioning

confidence: 99%

Using Mechanical Alloying to Create Bimetallic Catalysts for Vapor-Phase Carbon Nanofiber Synthesis

Guevara

Wanner

Welsh

et al. 2015

Fibers

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Carbon nanofibers were generated over bimetallic catalysts in an atmospheric pressure chemical vapor deposition (APCVD) reactor. Catalyst compositions of Fe 30 at%, Cu and Ni 30 at% and Cu were mechanically alloyed using high-energy ball milling over durations of 4,8,12,16, and 20 h. The catalyst powders were then used to produce carbon nanofibers in ethylene and hydrogen (4:1) at temperatures of 500, 550, and 600 °C. The microstructures of the catalysts were characterized as a function of milling time as well as at deposition temperature. The corresponding carbon deposition rates were assessed and are correlated to the microstructural features of each catalyst. The milling process directly determines the performance of each catalyst toward carbon deposition, and both catalysts performed comparably to those made by traditional co-precipitation methods. Considerations in miscible and immiscible nanostructured alloy systems are discussed.

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Section: Processing Considerationsmentioning

confidence: 99%

Using Mechanical Alloying to Create Bimetallic Catalysts for Vapor-Phase Carbon Nanofiber Synthesis

Guevara

Wanner

Welsh

et al. 2015

Fibers

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“…Car bons formed by decomposition on Fe, Ni, or Co of gas mixtures containing CO, CHj, and other small hydrocarbons have intermediate structure between graphi tizing and nongraphitizing. 5 The carbon literature contains numerous reports dealing with the characterization of porous carbons by adsorption of probe molecules and the effect of the heating protocol on total pore volume and pore size. There is little Information, however, about the relationship between precursor structure and pore structure of carbon.…”

Section: Carbon Membranesmentioning

confidence: 99%

Synthesis of Porous Inorganic Membranes

Tsapatsis¹,

Gavalas²

1999

MRS Bull.

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Here we will attempt a brief overview of recent synthetic efforts for micropore and lower-end mesopore membranes. We will not address the very important classes of nonporous membranes, such as dense metals and solid electrolytes with applications in H2 and O2 separations, or meso- and macroporous membranes, which find applications in food processing and water treatment. Microporous materials provide high permselectivities for molecules encountered in the chemical-processing industry but suffer from low intrinsic permeabilities. Therefore, in order to bring microporous membrane materials to commercial applications, functional composites with small effective thicknesses (in the micron or submicron range) must be developed. For example, to achieve economical membrane-reactor sizes, fluxes as high as 0.1 mol/(m2 s) are desirable. Approaches to microporous membranes include modification of mesoporous membranes by sol-gel and chemical-vapor-deposition (CVD) techniques, carbonization of polymers to form molecular-sieve carbon, and polycrystalline-film growth of zeolites and other molecular sieves.Microporous carbon is widely used for liquid or gas purification because of its strong adsorptive properties and high surface area. It is also used for air separation by pressure swing adsorption (PSA), relying on its adsorptive and molecular-sieving properties. From the standpoint of applications, microporous carbons are classified into activated carbons with pore size 0.8–2 nm, and ultramicroporous carbons or carbon molecular sieves with pores 0.3–0.6 nm. Activated carbons are used because of their strong adsorption properties, while carbon molecular sieves are useful on account of their molecular-sieving as well as adsorption properties.

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“…They suggested that in the hydrogen atmosphere, the active sites responsible for the decomposition of the carbon-gas interface were kept "clean" by H 2 . They also claimed that the higher the relative amount of hydrogen, the smaller amount of amorphous carbon were observed [16,21].…”

Section: Introductionmentioning

confidence: 99%

“…In that process iron-family transition metals were frequently used as catalysts [12,13,[16][17][18]. Supported Ni catalysts showed very high activity and the longest life for the decomposition of molecules containing * corresponding author; e-mail: barbara.liszka@cmpw-pan.edu.pl carbon atoms at temperatures 773-873 K [12,19].…”

Section: Introductionmentioning

confidence: 99%

“…Then the carbon atoms precipitate on the opposite surface of the catalyst particle and incorporate into graphene layers. Jablonski et al [16] implied that the presence of hydrogen was a necessary factor in determining the morphology of the formed carbon. They suggested that in the hydrogen atmosphere, the active sites responsible for the decomposition of the carbon-gas interface were kept "clean" by H 2 .…”

Section: Introductionmentioning

confidence: 99%

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Carbon Nanomaterials from Carbon Monoxide Using Nickel and Cobalt Catalysts

2010

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Two catalysts, nickel and cobalt, supported on MgO were used for carbon nanomaterials deposition by CO disproportionation. The syntheses were performed at 795 and 900 K in the hydrogen atmosphere. The resulting products were investigated using atomic force microscopy, scanning electron microscopy, and high-resolution transmission electron microscopy. Although in the literature carbon nanofibres are expected to form in the hydrogen presence, we obtained carbon nanotubes, which were multiwall and twisted with the outer diameter of 10-120 nm and the tube length up to 10 µm.

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Carbon deposition over Fe, Ni, and Co foils from CO-H2-CH4-CO2-H2O, CO-CO2, CH4-H2, and CO-H2-H2O gas mixtures: I. Morphology

Cited by 76 publications

References 43 publications

Using Mechanical Alloying to Create Bimetallic Catalysts for Vapor-Phase Carbon Nanofiber Synthesis

Using Mechanical Alloying to Create Bimetallic Catalysts for Vapor-Phase Carbon Nanofiber Synthesis

Synthesis of Porous Inorganic Membranes

Carbon Nanomaterials from Carbon Monoxide Using Nickel and Cobalt Catalysts

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