On the use of new oxidized Co–Cr–Pt–O catalysts for vertically-aligned few-walled carbon nanotube forest synthesis in electron cyclotron resonance chemical vapor deposition

Teng, I-Ju; Huang, Chong-Sian; Hsu, Hui-Lin; Chung, I-Chuan; Kherani, Nazir P.; Kuo, C. C.; Juang, Jenh‐Yih

doi:10.1016/j.carbon.2014.09.040

Cited by 6 publications

(4 citation statements)

References 66 publications

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“…In carbon nanofibers growth, many researchers studied this synergism of Pd or Pt combined with a transition metal. Atwater, Phillips, and Leseman used Pd with Co [22] and Teng et al used Pt with Co-Cr [23] found a high increase in the growth rate of CNTs, combining a transition and a noble metal. In the first case, the reactants were C 2 H 2 and H 2 , and in the second case, the reactants were CH 4 and H 2 .…”

Section: H Spillover Effect: An Illusion?mentioning

confidence: 99%

“…In the presence of Pt or Pd, H 2 splits easily into two atoms. H atoms diffuse easily through several metals, and other solids and can diffuse easily through a silica wafer [22] or a ceramic boat [23], as used in either experimental work mentioned above. The transition metal nanoparticle can be an alloy, such as Ni-Cu or Co-Cr.…”

Section: H Spillover Effect: An Illusion?mentioning

confidence: 99%

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Mechanism of Catalytic CNTs Growth in 400–650 °C Range: Explaining Volcano Shape Arrhenius Plot and Catalytic Synergism Using both Pt (or Pd) and Ni, Co or Fe

Lobo

2019

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The Arrhenius plot of catalytic carbon formation from olefins on Ni, Co, and Fe has a volcano shape in the range 400–550 °C with reaction orders 0 (at lower T: Below ~500 °C) and one (at higher T: Above ~500 °C) at each side of the maximum rate. The reaction follows a catalytic route with surface decomposition of the gas (olefin) on the catalyst nanoparticle, followed by the bulk diffusion of carbon atoms and carbon nanotube growth on the opposite side. At the higher temperature region (500–550 °C), the initial surface reaction step controls the rate and the reaction order is one, both in olefins and hydrogen (H). This confirms that H is essential for the surface reaction to occur. This is very valuable information to get faster CNT growth rate at relatively low temperatures. The apparent activation energy observed must correspond with the surface reaction Ea corrected for the temperature dependence of the two molecules involved (olefin and H). Adding a noble metal (Pt, Pd) to the carbon formation catalyst is frequently found to increase the reaction rate further. This effect has been described as an H spillover since 1964. However, there is evidence that the bulk diffusion of H atoms prevails and does not “spillover” the surface diffusion. Diffusion of H atoms through the solids involved is easy, and the H atoms remain single (“independent”) until emerging on a surface.

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Section: H Spillover Effect: An Illusion?mentioning

confidence: 99%

Section: H Spillover Effect: An Illusion?mentioning

confidence: 99%

Mechanism of Catalytic CNTs Growth in 400–650 °C Range: Explaining Volcano Shape Arrhenius Plot and Catalytic Synergism Using both Pt (or Pd) and Ni, Co or Fe

Lobo

2019

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“…Kiang et al suggested that synergistic effects of large bi-metal catalyst, such as Co and Bi, result in the expansion of CNT diameters [ 18 ]. Teng et al synthesized CNTs from the Co-Cr-Pt-O catalytic system and attributed simply the synergistic effect for growth [ 19 ]. Researchers also reported that tungsten, molybdenum, and sulfur could be used as the auxiliary catalyst to improve catalyst activity and increase the yield of carbon nanotubes [ 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Field Emission of Multi-Walled Carbon Nanotubes from Pt-Assisted Chemical Vapor Deposition

et al. 2022

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Multi-walled carbon nanotubes (MWNTs) were grown directly on a metal substrate with the assistance of Pt using a chemical vapor deposition method. In addition, the growth mechanism of Pt-assisted catalytic CNT was discussed. MWNTs were characterized by SEM, TEM, AFM, Raman, and EDS, and the field emission (FE) properties were investigated, comparing with the direct grown MWNTs. The results showed that CNTs could not been synthesized by Pt particles alone under the experimental condition, but Pt may accelerate the decomposition of the carbon source gas, i.e., assisting MWNT growth with other catalysts. The Pt-assisted MWNTs were longer with larger diameters of around 80 nm and possessed better structural qualities with very few catalyst particles inside. Improved field emission properties were demonstrated for the Pt-assisted MWNTs with lower turn-on fields (for 0.01 mA·cm−2 current density) of 2.0 V·μm−1 and threshold field (for 10 mA·cm−2 current density) of 3.5 V·μm−1, as well as better stability under a long-term test of 80 h (started at 3.0 mA for the Pt-assisted emitter and 3.25 mA for the direct grown emitter). This work demonstrated a promising approach to develop high performance CNT field emitters for device applications.

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“…Land et al., (1992) investigated the growth and nature of a graphite layer during decomposition of ethylene. However, it seems that carbon filaments (nanotubes and nanofibres) (Anoshkin et al., 2014; Mizutani et al., 2012; Takenaka et al., 2004a; Teng et al., 2014; Willems et al., 2000; Zhang and Zhang, 2013; Zou et al., 2006) are the most often described and investigated group. The formation of carbon nanotubes/nanofibres on the catalyst’s surface is a desirable form.…”

Section: Introductionmentioning

confidence: 99%

Nanostructured forms of carbon deposit obtained during cracking of methane reaction over nanocrystalline iron catalysts

Maj

Kocemba

2017

Adsorption Science & Technology

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During catalytic cracking of methane reaction, different carbon nanostructures can be formed. This paper shows the results of a characteristic nanostructured carbon deposit obtained during cracking of methane reaction over nanocrystalline iron catalysts with or without cobalt addition. The properties of the carbon deposit were determined by X-ray diffraction, scanning electron microscope with energy dispersive spectrometer equipment, thermogravimetry-differential thermal analysis coupled with mass spectrometry, time-of-flight secondary ion mass spectrometry analysis and surface area analysis (Brunauer-Emmett-Teller isotherm [BET]). Significant differences in the morphology and properties of the obtained carbon were found. The mechanism of the formation of carbon nanostructures for both iron catalysts is proposed.

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On the use of new oxidized Co–Cr–Pt–O catalysts for vertically-aligned few-walled carbon nanotube forest synthesis in electron cyclotron resonance chemical vapor deposition

Cited by 6 publications

References 66 publications

Mechanism of Catalytic CNTs Growth in 400–650 °C Range: Explaining Volcano Shape Arrhenius Plot and Catalytic Synergism Using both Pt (or Pd) and Ni, Co or Fe

Mechanism of Catalytic CNTs Growth in 400–650 °C Range: Explaining Volcano Shape Arrhenius Plot and Catalytic Synergism Using both Pt (or Pd) and Ni, Co or Fe

Field Emission of Multi-Walled Carbon Nanotubes from Pt-Assisted Chemical Vapor Deposition

Nanostructured forms of carbon deposit obtained during cracking of methane reaction over nanocrystalline iron catalysts

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