Different degrees of weak metal–support interaction in Fe–(Ni)/Al2O3 catalyst governing activity and selectivity in carbon nanotubes’ production using ethylene

Ratkovic, Sanja; Vujicic, Dj.; Kiss, Ernő E.; Bošković, Goran; Geszti, O.

doi:10.1016/j.matchemphys.2011.04.036

Cited by 51 publications

(22 citation statements)

References 30 publications

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“…1) and other researchers 36,37 . In addition, according to Ayub et al 38 and Ratkovic et al 39 , the reduction peaks at around 420, 550 and 800 °C can be assigned as the reduction ofFe2O3. A two-step reduction of Fe-oxide has been reported (Fe2O3->Fe3O4->Fe or Fe2O3->Fe3O4->FeO->Fe), which was depended on the composition and the weight of the sample, and the particle size of metal oxides 40 .…”

Section: Tpr Analysismentioning

confidence: 90%

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Development of Fe-Promoted Ni–Al Catalysts for Hydrogen Production from Gasification of Wood Sawdust

Dong

Ling

et al. 2016

Energy Fuels

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ABSTRACT:The production of renewable hydrogen enriched gas from biomass waste is a promising technology for the development of a sustainable economy and society. Until now, there are still challenges of the technology in terms of the efficiency of hydrogen production. Catalyst is known and has been tested to enhance hydrogen production from biomass gasification. In particular using Ni-based catalysts, which have high reactivity for hydrogen production and are cost effective. However, developing a Ni-based catalyst with high thermal stability and resistance of coke deposition on the surface of the catalyst is still a challenging topic. In this work, Ni-Al catalysts doped with low-cost Fe metal were investigated for hydrogen enriched syngas production from gasification of biomass using a two-stage fixed bed reactor. NiOFe2O3-Al2O3 catalysts with various Ni:Fe molar ratios (9:1, 8:2, 6:4, 5:5, 4:6, 2:8 and 1:9) were studied aiming to understand the influence of Fe addition on the production of hydrogen and the catalyst stability in terms of coke deposition on surface. X-ray diffraction, temperature programme reduction and Transmission electron microscopy analysis of the fresh catalysts showed that nanoparticles (mainly NiAl2O4 spinel phase and Al2O3, ~5 nm) were identified in the catalysts. High dispersion of metal particles was obtained using a co-precipitation method of catalyst preparation. With the increase of Fe addition, hydrogen production was reduced from around 11 to 8 (mmol H2 g -1 biomass). However, the addition of Fe into the Ni-based catalyst significantly reduced the amount of coke deposited on the surface of the catalyst.H2/CO molar ratio was maximized to 1.28 when Ni:Fe molar ratio was 1:1. In addition, sintering of metal particles was not observed through the TEM analysis of the fresh and reacted catalysts.2

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Section: Tpr Analysismentioning

confidence: 90%

“…The maximum reduction temperature was slightly increased to 830 °C and the width of the peak was enhanced with the increase of Fe content, indicating more metal oxide species were reduced and the reducibility was reduced for the bimetallic catalysts 39 .…”

Section: Tpr Analysismentioning

confidence: 99%

Development of Fe-Promoted Ni–Al Catalysts for Hydrogen Production from Gasification of Wood Sawdust

Dong

Ling

et al. 2016

Energy Fuels

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“…3a) where the metal nanoparticles were found at the end of the nanotubes. According to Ratkovic et al, the "tip-growth" mechanism of the MWCNTs indicates the week metal-support interaction [21]. (Fig.…”

Section: Relationship Between the Catalyst Sizes And Carbon Nanotubesmentioning

confidence: 99%

“…The carbons formed on polycrystalline metal nanoparticles were grown predominately by the "tipgrowth" mechanism. It can be explained by predominantly weak metal-support interaction [21].…”

Section: The Relationship Between the Catalyst Sizes And Carbon Nanotmentioning

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 MWCNTs synthesis was carried out for 2 h in flow of ethylene/nitrogen mixture (1:1) at 700°C, using in situ pre-reduced catalyst, in a home-made reactor setup that was described earlier (Ratkovic et al, 2009(Ratkovic et al, , 2011. The catalyst performed with high activity and selectivity to MWCNTs, measured as carbon yield of 264% and with no traces of amorphous carbon.…”

Section: Synthesis and Oxidation Of Multi-walled Carbon Nanotubes (Mwmentioning

confidence: 99%

Optimization of thiamethoxam adsorption parameters using multi-walled carbon nanotubes by means of fractional factorial design

et al. 2015

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Different degrees of weak metal–support interaction in Fe–(Ni)/Al2O3 catalyst governing activity and selectivity in carbon nanotubes’ production using ethylene

Cited by 51 publications

References 30 publications

Development of Fe-Promoted Ni–Al Catalysts for Hydrogen Production from Gasification of Wood Sawdust

Development of Fe-Promoted Ni–Al Catalysts for Hydrogen Production from Gasification of Wood Sawdust

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

Optimization of thiamethoxam adsorption parameters using multi-walled carbon nanotubes by means of fractional factorial design

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