Evolution of the structure of unpromoted and potassium-promoted ceria-supported nickel catalysts in the steam reforming of ethanol

Słowik, Grzegorz; Greluk, Magdalena; Rotko, Marek; Machocki, Andrzej

doi:10.1016/j.apcatb.2017.09.052

Cited by 58 publications

(31 citation statements)

References 62 publications

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“…Similar effects can be obtained by the decrease of metal crystallite size, which result in the increase of metal-support border-line, and increase of the rate of surface reactions with participation of hydroxyl groups or redox sites on the support. The decrease of the rate of filamentous carbon deposit formation by the decrease of nickel crystallite size in ESR reaction in the Ni/CeO 2 catalysts has been recently evidenced by Slowik et al [73]. Fig.…”

Section: The Nature Of Carbon Depositsmentioning

confidence: 66%

“…The presence of CO in the reaction products can be also connected with conversion of ethanol or formed acetaldehyde with participation of the smaller number of water molecules (C 2 H 5 OH + H 2 O → 4H 2 + 2CO, CH 3 CHO + H 2 O → 3H 2 + CO), and low activity of catalysts in consecutive water-gas shift reaction (CO + H 2 O → CO 2 + H 2 ). High nickel dispersion has been often regarded as the most important feature of ESR nickel catalysts [72,73]. The decrease of nickel crystallite size led to the increase of the number of active sites, as well as to the changes of their nature, related with different crystallite geometry and contribution of suitable sites (face, edge and corner atoms) [74,75].…”

Section: H2mentioning

confidence: 99%

“…The decrease of nickel crystallite size led to the increase of the number of active sites, as well as to the changes of their nature, related with different crystallite geometry and contribution of suitable sites (face, edge and corner atoms) [74,75]. An improved activity, selectivity, as well as better sintering and coking resistance has been often presented for the catalysts with the small crystallites in the ESR reaction [72,73]. It was demonstrated, that both Ni 10 HAlBEA and Ni 10 SiBEA catalysts showed high initial activity in the ethanol steam reforming reaction.…”

Section: H2mentioning

confidence: 99%

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Effects of dealumination on the performance of Ni-containing BEA catalysts in bioethanol steam reforming

Gac

Greluk

Słowik

et al. 2018

Applied Catalysis B: Environmental

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The effects of dealumination of BEA zeolite on the formation of nickel active sites and the performance of Nicontaining BEA zeolite catalysts in the steam reforming of ethanol have been studied. Ni-containing BEA zeolite catalysts were prepared by the impregnation of unmodified and dealuminated BEA zeolites with Ni(NO 3) 2 precursor. The properties of Ni 10 HAlBEA and Ni 10 SiBEA zeolite catalysts were studied by means of X-ray diffraction, 1 H, 27 Al and 29 Si magic-angle spinning nuclear magnetic resonance, Fourier-transform infrared and Raman spectroscopy, transmission electron microscopy, temperature-programmed reduction, temperature-programmed ammonia and hydrogen desorption methods. High initial activity and selectivity of Ni 10 HAlBEA to hydrogen and carbon dioxide with unmodified BEA zeolite support in the steam reforming of ethanol reaction performed at 500°C was observed. However, fast deactivation of Ni 10 HAlBEA catalyst, manifested in the decrease of water conversion, drop of selectivity to H 2 and CO 2 , and increase in the selectivity to ethylene with the time-on-stream, was observed. In contrast, Ni 10 SiBEA zeolite catalyst showed lower initial activity but higher durability and resistance for carbon deposition. It was stated that dealumination of BEA zeolite led to the slight structural changes and simultaneously pronounced decrease of acidity. Formation of the large nickel crystallites was hindered on Ni 10 SiBEA zeolite catalyst. TEM and Raman spectroscopy studies indicated that deactivation of Ni 10 HAlBEA was related to formation of nickel mediated filamentous, graphitic and amorphous carbon deposits. Much smaller amounts of filamentous carbons were observed on the Ni 10 SiBEA zeolite catalyst prepared by the use of dealuminated zeolite support.

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Section: The Nature Of Carbon Depositsmentioning

confidence: 66%

Section: H2mentioning

confidence: 99%

Section: H2mentioning

confidence: 99%

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Effects of dealumination on the performance of Ni-containing BEA catalysts in bioethanol steam reforming

Gac

Greluk

Słowik

et al. 2018

Applied Catalysis B: Environmental

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“…Therefore, the carbonaceous fibers formed on both catalysts are different. The unpromoted potassium Ni/CeO 2 catalyst forms long/thick and short/thin graphitic fibers, while the promoted potassium Ni/CeO 2 forms only long/thick graphitic fibers, which are longer and thicker than those of the unpromoted catalyst . In contrast, the co‐addition of K and CeO 2 showed a promising catalytic performance and less carbon deposition in the ESR , .…”

Section: Effects Of the Promotersmentioning

confidence: 95%

Effect of Supports and Promoters on the Performance of Ni‐Based Catalysts in Ethanol Steam Reforming

et al. 2020

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Ethanol steam reforming (ESR) is one of the potential processes to convert ethanol into valuable products. Hydrogen produced from ESR is considered as green energy for the future and can be an excellent alternative to fossil fuels with the aim of mitigating the greenhouse gas effect. The ESR process has been well studied, using transition metals as catalysts coupled with both acidic and basic oxides as supports. Among various reported transition metals, Ni is an inexpensive material with activity comparable to that of noble metals, showing promising ethanol conversion and hydrogen yields. Additionally, different promoters and supports were utilized to enhance the hydrogen yield and the catalyst stability. This review summarizes and discusses the influences of the supports and promoters of Ni‐based catalysts on the ESR process.

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“…Recently, much attention has been paid to hydrogen preparation from reforming reactions starting from methanol [13][14][15] and especially ethanol [16][17][18], which has a 1.5-fold higher hydrogen concentration per mole than methanol. Moreover, the biomass Ethanol-water solution (8-15% v/v) or crude distillation of concentrated solution (15-50% v/v) generated from biomass conversion can be directly used for reforming reaction for hydrogen generation.…”

Section: Introductionmentioning

confidence: 99%

Hydrogenation of m-Chloronitrobenzene over Different Morphologies Ni/TiO2 without Addition of Molecular Hydrogen

Liang

Zhu

et al. 2018

Catalysts

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Ni/TiO 2 catalysts with different morphologies (granular, sheet, tubular and spherical) were prepared. Hydrogen was generated from ethanol aqueous-phase reforming over Ni/TiO 2 in a water-ethanol-m-chloronitrobenzene reaction system and directly applied into m-chloronitrobenzene catalytic hydrogenation. Thereby, in-situ liquid-phase hydrogenation of m-chloronitrobenzene over Ni/TiO 2 without addition of molecular hydrogen was successful. Compared with granular, sheet and spherical Ni/TiO 2 , the nanotubular Ni/TiO 2 prepared from one-step hydrothermal reaction had larger specific surface area, smaller and uniformly-distributed pore sizes and more Lewis acid sites. In-situ liquid-phase hydrogenation of m-chloronitrobenzene experiments showed the nanotubular Ni/TiO 2 had the highest catalytic activity, which was ascribed to both catalyst morphology and acid sites. Firstly, the nanotubular structure endowed the catalysts with a nanoscale confinement effect and thereby high catalytic performance. Secondly, the Lewis acid sites not only accelerated water-gas shift reaction, enhancing the ethanol aqueous-phase reforming activity for hydrogen generation, but also promoted the adsorption and hydrogenation of-NO 2 on the active sites of the catalysts.

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Evolution of the structure of unpromoted and potassium-promoted ceria-supported nickel catalysts in the steam reforming of ethanol

Cited by 58 publications

References 62 publications

Effects of dealumination on the performance of Ni-containing BEA catalysts in bioethanol steam reforming

Effects of dealumination on the performance of Ni-containing BEA catalysts in bioethanol steam reforming

Effect of Supports and Promoters on the Performance of Ni‐Based Catalysts in Ethanol Steam Reforming

Hydrogenation of m-Chloronitrobenzene over Different Morphologies Ni/TiO2 without Addition of Molecular Hydrogen

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