Relationship between the Structure/Composition of Co–Mo Catalysts and Their Ability to Produce Single-Walled Carbon Nanotubes by CO Disproportionation

Herrera, José E.; Balzano, Laura; Borgna, Armando; Alvarez, Walter E.; Resasco, Daniel E.

doi:10.1006/jcat.2001.3383

Cited by 195 publications

(170 citation statements)

References 45 publications

(29 reference statements)

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“…Another research was focused on the application of the aluminium substrate, and found wide application in industrial production [123].…”

Section: Cobalt and Molybdenum (Como) Cat Processmentioning

confidence: 99%

“…Mo forms small clusters of well-dispersed Mo 6+ particles, which interact with Co, forming a Co-molybdate-like structure. Under reaction conditions, Mo oxide species are converted into Mo carbide, releasing the metallic Co in a state of high dispersion, which forces the formation of SWNT [123]. Otherwise, in the case of the presence of Co only or at a high Co:Mo ratio interacts into a nonselective Co 3 O 4 phase, which further reduces to metallic Co. Large metallic Co clusters handle the formation of MWNT, filaments, graphite and other side products.…”

Section: Cobalt and Molybdenum (Como) Cat Processmentioning

confidence: 99%

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Carbon nanotubes for ultrafast fibre lasers

et al. 2016

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Carbon nanotubes (CNTs) possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNTbased saturable absorbers (CNT-SA), their integration and operation in fibre laser cavities putting emphasis on stateof-the-art fibre lasers, mode locked using CNT-SA. We discuss new design concepts of high-performance ultrafast operation fibre lasers covering ytterbium (Yb), bismuth (Bi), erbium (Er), thulium (Tm) and holmium (Ho)-doped fibre lasers.

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“…Another research was focused on the application of the aluminium substrate, and found wide application in industrial production [123].…”

Section: Cobalt and Molybdenum (Como) Cat Processmentioning

confidence: 99%

Section: Cobalt and Molybdenum (Como) Cat Processmentioning

confidence: 99%

Carbon nanotubes for ultrafast fibre lasers

et al. 2016

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“…However, relatively few articles report detailed studies on the starting material. [5][6][7] We have proposed an original CCVD method 8 using oxide solid solutions as the starting materials. Indeed, the reduction in a H 2 /CH 4 atmosphere of R-Al 1.9 Fe 0.1 O 3 , in which the ferric ions are well dispersed, produces pristine Fe nanoparticles at a temperature high enough for them to catalyze the decomposition of CH 4 and the in situ formation of CNTs including single-walled CNTs (SWNTs).…”

Section: Introductionmentioning

confidence: 99%

Carbon Nanotubes by a CVD Method. Part II: Formation of Nanotubes from (Mg, Fe)O Catalysts

et al. 2002

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 10385 The aim of this paper is to study the formation of carbon nanotubes (CNTs) from different Fe/MgO oxide powders that were prepared by combustion synthesis and characterized in detail in a companion paper. Depending on the synthesis conditions, several iron species are present in the starting oxides including Fe 2+ ions, octahedral Fe 3+ ions, Fe 3+ clusters, and MgFe 2 O 4 -like nanoparticles. Upon reduction during heating at 5°C/min up to 1000°C in H 2 /CH 4 of the oxide powders, the octahedral Fe 3+ ions tend to form Fe 2+ ions, which are not likely to be reduced to metallic iron whereas the MgFe 2 O 4 -like particles are directly reduced to metallic iron. The reduced phases are R-Fe, Fe 3 C, and γ-Fe-C. Fe 3 C appears as the postreaction phase involved in the formation of carbon filaments (CNTs and thick carbon nanofibers). Thick carbon nanofibers are formed from catalyst particles originating from poorly dispersed species (Fe 3+ clusters and MgFe 2 O 4 -like particles). The nanofiber outer diameter is determined by the particle size. The reduction of the iron ions and clusters that are well dispersed in the MgO lattice leads to small catalytic particles (<5 nm), which tend to form SWNTS and DWNTs with an inner diameter close to 2 nm. Well-dispersed MgFe 2 O 4 -like particles can also be reduced to small metal particles with a narrow size distribution, producing SWNTs and DWNTs. The present results will help in tailoring oxide precursors for the controlled formation of CNTs.

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“…The features observed below 500°C are similar to those observed for monometallic Fe oxide catalyst supported on alumina, which have been related to the three phases of reduction of iron oxide in the form of hematite to metallic Fe (transformation of Fe 2 O 3 f Fe 3 O 4 f FeO f Fe). 9 The high temperature peak (∼830°C), which could be related to residual oxygen in the smaller metal particles 10 and the effect of Mo, shows that the common reduction procedure 11,12 at ∼500°C under a flow of He/H 2 is not enough to completely reduce the metal catalyst in † Honda Research Institute USA Inc. ‡ Rice University. the sample.…”

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confidence: 99%

Low-Temperature Single-Wall Carbon Nanotubes Synthesis: Feedstock Decomposition Limited Growth

et al. 2008

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We report on the lowest temperature of SWCNT growth using endothermic decomposition of CH4 gas on a specially activated alumina-supported Fe:Mo catalyst. However, the observed lowest growth temperature (560 °C) is higher than that reported previously for exothermic feedstock type. Our observation indicates that the decomposition threshold temperature of the feedstock limits the SWCNT growth. This study also suggests that, by using more active carbon feedstock or somehow facilitating its decomposition, one could enable the synthesis of SWCNT at an even lower temperature.

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Relationship between the Structure/Composition of Co–Mo Catalysts and Their Ability to Produce Single-Walled Carbon Nanotubes by CO Disproportionation

Cited by 195 publications

References 45 publications

Carbon nanotubes for ultrafast fibre lasers

Carbon nanotubes for ultrafast fibre lasers

Carbon Nanotubes by a CVD Method. Part II: Formation of Nanotubes from (Mg, Fe)O Catalysts

Low-Temperature Single-Wall Carbon Nanotubes Synthesis: Feedstock Decomposition Limited Growth

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