Rational design of the carbon nanofiber catalysts for oxidative dehydrogenation of ethylbenzene

Zhao, Tong; Sun, Weizhen; Gu, Xingsheng; Rønning, Magnus; Chen, De; Dai, Yang; Wang, Yuan; Holmén, Anders

doi:10.1016/j.apcata.2007.02.008

Cited by 94 publications

(72 citation statements)

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“…[197][198] They showed that it is possible to tune the orientation of the graphene sheets between 08 and 908 relative to the axis of the nanofilament. The temperature and the nature of the gas feed induce a reconstruction of the metal nanoparticles.…”

Section: Effect Of Reaction Conditionsmentioning

confidence: 99%

Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review

2011

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Tremendous progress has been achieved during the past 20 years on not only improving the yields of carbon nanotubes and move progressively towards their mass production, but also on gaining a profound fundamental understanding of the nucleation and the growth processes. Parameters that influence the yield but also the quality (e.g., microstructure, homogeneity within a batch) are better understood. The influence of the carbon precursor, the reaction conditions, the presence of a catalyst, the chemical and physical status of the latter, and other factors have been extensively studied. The purpose of the present Review is not to list all the experiments reported in the literature, but rather to identify trends and provide a comprehensive summary on the role of selected parameters. The role of the catalyst occupies a central place in this Review as a careful control of the metal particle size, particle dispersion on the support, the metastable phase formed under reaction conditions, its possible reconstruction, and faceting strongly influence the diameter of the carbon nanotubes, their structure (number of walls, graphene sheet orientation, chirality), their alignment, and the yield. The identified trends will be compared with recent observations on the growth of graphene. Recent results on metal-free catalysts will be analyzed from a different perspective.

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Section: Effect Of Reaction Conditionsmentioning

confidence: 99%

Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review

2011

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“…The oxidative dehydrogenation (ODH) process of ethylbenzene to styrene in the presence of oxidant has attracted considerable attention because it can be operated at lower temperatures and ethylbenzene conversion would not be equilibrium limited. 7,8 A variety of oxidizing agents, such as O 2 , N 2 O, SO 2 and CO 2 , have been used for the oxidative dehydrogenation of ethylbenzene to lower the reaction temperature. 5,9−12 Exploitation of CO 2 as a soft oxidant for the commercial catalytic ODH of ethylbenzene to styrene has received enormous interest recently because of several benefits of using CO 2 compared with other oxidants.…”

Section: ■ Introductionmentioning

confidence: 99%

Role Of CO₂ As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst

Zhang¹,

Wu²,

Nelson

et al. 2015

ACS Catal.

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Catalytic performance and the nature of surface adsorbates were investigated for high-surface-area ceria during the ethylbenzene oxidative dehydrogenation (ODH) reaction using CO2 as a soft oxidant. The high surface area ceria material was synthesized using a template-assisted method. The interactions among ethylbenzene, styrene, and CO2 on the surface of ceria and the role of CO2 for the ethylbenzene ODH reaction have been investigated in detail by using activity test, in situ diffuse reflectance infrared and Raman spectroscopy. CO2 as an oxidant not only favored the higher yield of styrene but also inhibited the deposition of coke during the ethylbenzene ODH reaction. Ethylbenzene ODH reaction over ceria followed a two-step pathway: ethylbenzene is first dehydrogenated to styrene with H2 formed simultaneously, and then CO2 reacts with H2 via the reverse water gas shift. The produced styrene can easily undergo polymerization to form polystyrene, which is a key intermediate for coke formation. In the absence of CO2, the produced polystyrene transforms into graphite-like coke at temperatures above 500 °C, which leads to catalyst deactivation. In the presence of CO2, the coke deposition can be effectively removed via oxidation with CO2. ABSTRACT: Catalytic performance and the nature of surface adsorbates were investigated for high-surface-area ceria during the ethylbenzene oxidative dehydrogenation (ODH) reaction using CO 2 as a soft oxidant. The high surface area ceria material was synthesized using a template-assisted method. The interactions among ethylbenzene, styrene, and CO 2 on the surface of ceria and the role of CO 2 for the ethylbenzene ODH reaction have been investigated in detail by using activity test, in situ diffuse reflectance infrared and Raman spectroscopy. CO 2 as an oxidant not only favored the higher yield of styrene but also inhibited the deposition of coke during the ethylbenzene ODH reaction. Ethylbenzene ODH reaction over ceria followed a two-step pathway: ethylbenzene is first dehydrogenated to styrene with H 2 formed simultaneously, and then CO 2 reacts with H 2 via the reverse water gas shift. The produced styrene can easily undergo polymerization to form polystyrene, which is a key intermediate for coke formation. In the absence of CO 2 , the produced polystyrene transforms into graphite-like coke at temperatures above 500°C, which leads to catalyst deactivation. In the presence of CO 2 , the coke deposition can be effectively removed via oxidation with CO 2 .

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“…[5,8,9] CNFs have been used as a catalyst for the ODH of ethylbenzene, in which the graphitic platelet orientation has a significant effect on the catalyst activity and selectivity. [10] In that case, the conversion was promoted by enhanced p-p interactions of the ethylbenzene phenyl ring with the carbon basal planes.…”

Section: Introductionmentioning

confidence: 96%

Carbon Nanofibers Modified with Heteroatoms as Metal‐Free Catalysts for the Oxidative Dehydrogenation of Propane

et al. 2014

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Carbon nanofibres (CNFs) were modified with B and P by an ex situ approach. In addition, CNFs doped with N were prepared in situ using ethylenediamine as the N and C source. After calcination, the doped CNFs were used as catalysts for the oxidative dehydrogenation of propane. For B-CNFs, the effects of boron loading and calcination temperature on B speciation and catalytic conversion were studied. For the same reaction temperatures and conversions, B- and P-doped CNFs exhibited higher selectivities to propene than pristine CNFs. The N-CNFs were the most active but the least selective of the catalysts tested here. Our results also show that the type of P precursor affects the selectivity to propene and that CNFs modified using triphenylphosphine as the precursor provided the highest selectivity at isoconversion.

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Rational design of the carbon nanofiber catalysts for oxidative dehydrogenation of ethylbenzene

Cited by 94 publications

References 50 publications

Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review

Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review

Role Of CO₂ As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst

Carbon Nanofibers Modified with Heteroatoms as Metal‐Free Catalysts for the Oxidative Dehydrogenation of Propane

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Rational design of the carbon nanofiber catalysts for oxidative dehydrogenation of ethylbenzene

Cited by 94 publications

References 50 publications

Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review

Recent Progress on the Growth Mechanism of Carbon Nanotubes: A Review

Role Of CO2 As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst

Carbon Nanofibers Modified with Heteroatoms as Metal‐Free Catalysts for the Oxidative Dehydrogenation of Propane

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Role Of CO₂ As a Soft Oxidant For Dehydrogenation of Ethylbenzene to Styrene over a High-Surface-Area Ceria Catalyst