Carbon nanotubes formation and its influence on steam reforming of toluene over Ni/Al2O3 catalysts: Roles of catalyst supports

He, Limo; Su, Sheng; Jiang, Long; Liao, Guoning; Chen, Xiaofang; Han, Hengda; Xiao, Lingfeng; Ren, Qiangqiang; Wang, Lele

doi:10.1016/j.fuproc.2018.03.007

Cited by 75 publications

(31 citation statements)

References 33 publications

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“…High GHSV, or lower residence time, might inhibit toluene conversion and H 2 production. Literature suggests that suitable GHSVs for steam reforming were mostly between 10,000 and 70,000 h −1 [38,39] over different catalysts. For our benchmark catalyst, tests were carried out with 500 mg of catalyst, and a fixed temperature (800 • C) and S/C ratio of three during 5 h of reaction.…”

Section: Influence Of Ghsv In Toluene Steam Reformingmentioning

confidence: 99%

Catalytic Steam Reforming of Toluene: Understanding the Influence of the Main Reaction Parameters over a Reference Catalyst

2020

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Identifying the suitable reaction conditions is key to achieve high performance and economic efficiency in any catalytic process. In this study, the catalytic performance of a Ni/Al2O3 catalyst, a benchmark system—was investigated in steam reforming of toluene as a biomass gasification tar model compound to explore the effect of reforming temperature, steam to carbon (S/C) ratio and residence time on toluene conversion and gas products. An S/C molar ratio range from one to three and temperature range from 700 to 900 °C was selected according to thermodynamic equilibrium calculations, and gas hourly space velocity (GHSV) was varied from 30,600 to 122,400 h−1 based on previous work. The results suggest that 800 °C, GHSV 61,200 h−1 and S/C ratio 3 provide favourable operating conditions for steam reforming of toluene in order to get high toluene conversion and hydrogen productivity, achieving a toluene to gas conversion of 94% and H2 production of 13 mol/mol toluene.

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Section: Influence Of Ghsv In Toluene Steam Reformingmentioning

confidence: 99%

Catalytic Steam Reforming of Toluene: Understanding the Influence of the Main Reaction Parameters over a Reference Catalyst

2020

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“…For example, Souza et al observed that the filamentous carbon formation at different activation conditions could increase the stability and activity of the catalyst during CO 2 reforming of methane. Many researchers confirmed that filamentous carbons formed during steam reforming process were in the shape of carbon nanotubes (CNTs) . CNTs have attracted considerable attentions worldwide because of their particular physical and chemical properties and have a number of applications that have prospects in application to biomedicine, catalysis, electronics, and hydrogen storage.…”

Section: Introductionmentioning

confidence: 99%

“…Many researchers confirmed that filamentous carbons formed during steam reforming process were in the shape of carbon nanotubes (CNTs). 18,19 CNTs have attracted considerable attentions worldwide because of their particular physical and chemical properties and have a number of applications that have prospects in application to biomedicine, catalysis, electronics, and hydrogen storage. Because of the significant surface area and optimal adsorption property of CNTs, they are the preferred catalyst support in many areas.…”

Section: Introductionmentioning

confidence: 99%

Ethanol steam reforming on Ni/CaO catalysts for coproduction of hydrogen and carbon nanotubes

et al. 2019

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Summary Catalytic steam reforming of ethanol is considered as a promising technology for producing H2 in the modern world. In this study, using a fixed‐bed reactor, steam reforming of ethanol was performed for production of carbon nanotubes (CNTs) and H2 simultaneously at 600°C on Ni/CaO catalysts. Commercial CaO and a synthetic CaO prepared using sol‐gel were scrutinized for ethanol's catalytic steam reforming. Analysis results of N2 isothermal adsorption indicate that the CaO synthesized by sol‐gel has more pore volume and surface area in comparison with the commercial CaO. When Ni was loaded, the Ni/CaO catalyst shows an encouraging catalytic property for H2 production, and an increase in Ni loading could improve H2 production. The Ni/CaO catalyst with sol‐gel CaO support has presented a higher hydrogen production and better catalytic stability than the catalysts with the commercial CaO support at low Ni loading. The highest hydrogen yield is 76.8% at Ni loading content of 10% for the Ni/sol‐gel CaO catalyst with WHSV of 3.32/h and S/C ratio of 3. The carbon formed after steam reforming primarily consists of filamentous carbons and amorphous carbons, and CNTs are the predominant type of carbon deposition. The deposited extent of carbon on the used Ni/CaO catalyst lessen upon more Ni loading, and the elongated CNTs are desired to be formed at the surface of the Ni/sol‐gel CaO catalyst. Thus, an efficient process and improved economic value is associated with prompt hydrogen production and CNTs from ethanol steam reforming.

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“…Based on the widely accepted vapor-liquid-solid (VLS) mechanism, as shown in Fig. 11, the process 22,28,29 involves several steps of VLS growth in essence.…”

Section: Characterization Of Carbon Nanomaterials On Nickel Foam Subsmentioning

confidence: 99%

Flame Synthesis of Carbon Nanotubes on Different Substrates in Methane Diffusion Flames

Chu¹,

Han²,

Ren³

et al. 2018

ES Energy Environ.

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Characterized by their unique electrical, mechanical, and photonic properties, carbon nanotubes (CNTs) have generated a high level of research interest. Based on the study of methane coaxial jet diffusion flame, the effect of sampling substrate, sampling time and sampling height on the catalytic synthesis of CNTs was studied. The morphology and structure of carbon nanomaterials were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Raman spectroscopy. The interaction between the catalyst and the substrate was analyzed with nickel nitrate as catalyst precursor and copper, nickel-chromium and nickel foam as supported substrates, respectively. The experimental results showed that sampling time and sampling height had an important influence on CNTs. Copper and nickelchromium substrates provide open space for the synthesis of CNTs, resulting in more impurities. The unique voids of nickel foam provide excellent growth space for CNTs. SEM showed that the multi-walled CNTs were dense and uniform. TEM displayed that the catalyst particles were coated inside the CNTs. Raman spectroscopy indicated that the CNTs synthesized on copper substrates had the highest crystallinity and purity, followed by nickel-chromium and nickel foam substrates. The interaction between the catalyst and the substrate remarkably affected the growth mechanism and morphology of CNTs. The flame-synthesizing CNTs are based on the tip growth mode and the vapor-liquid-solid growth mechanism. Flame synthesis holds great potential for the cost-effective production of CNTs.

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Carbon nanotubes formation and its influence on steam reforming of toluene over Ni/Al2O3 catalysts: Roles of catalyst supports

Cited by 75 publications

References 33 publications

Catalytic Steam Reforming of Toluene: Understanding the Influence of the Main Reaction Parameters over a Reference Catalyst

Catalytic Steam Reforming of Toluene: Understanding the Influence of the Main Reaction Parameters over a Reference Catalyst

Ethanol steam reforming on Ni/CaO catalysts for coproduction of hydrogen and carbon nanotubes

Flame Synthesis of Carbon Nanotubes on Different Substrates in Methane Diffusion Flames

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