Effect of Ni/Al molar ratio on the performance of substoichiometric NiAl 2 O 4 spinel-based catalysts for partial oxidation of methane

Gil-Calvo, Miryam; Jiménez‐González, Cristina; Rivas, Beatriz de; Gutiérrez-Ortiz, José I.; López‐Fonseca, Rubén

doi:10.1016/j.apcatb.2017.02.063

Cited by 70 publications

(39 citation statements)

References 43 publications

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“…The reaction proceeds at a lower temperature than the gas-phase partial oxidation route [17][18][19][20], thus offering many advantages such as a reduction of undesired by-products and the ability to control the process temperature [21][22][23][24]. The catalysts used for this reaction usually contain group VIII transition metals, such as rhodium [25,26], ruthenium [27,28], platinum [29,30], palladium [31,32], nickel [33,34], iridium [35,36], and cobalt [37,38].…”

Section: Introductionmentioning

confidence: 99%

RETRACTED: Computational Fluid Dynamics Modeling of the Catalytic Partial Oxidation of Methane in Microchannel Reactors for Synthesis Gas Production

Chen

Song

2018

Processes

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This paper addresses the issues related to the favorable operating conditions for the small-scale production of synthesis gas from the catalytic partial oxidation of methane over rhodium. Numerical simulations were performed by means of computational fluid dynamics to explore the key factors influencing the yield of synthesis gas. The effect of mixture composition, pressure, preheating temperature, and reactor dimension was evaluated to identify conditions that favor a high yield of synthesis gas. The relative importance of heterogeneous and homogenous reaction pathways in determining the distribution of reaction products was investigated. The results indicated that there is competition between the partial and total oxidation reactions occurring in the system, which is responsible for the distribution of reaction products. The contribution of heterogeneous and homogeneous reaction pathways depends upon process conditions. The temperature and pressure play an important role in determining the fuel conversion and the synthesis gas yield. Undesired homogeneous reactions are favored in large reactors, and at high temperatures and pressures, whereas desired heterogeneous reactions are favored in small reactors, and at low temperatures and pressures. At atmospheric pressure, the selectivity to synthesis gas is higher than 98% at preheating temperatures above 900 K when oxygen is used as the oxidant. At pressures below 1.0 MPa, alteration of the dimension in the range of 0.3 and 1.5 mm does not result in significant difference in reactor performance, if made at constant inlet flow velocities. Air shows great promise as the oxidant, especially at industrially relevant pressure 3.0 MPa, thereby effectively inhibiting the initiation of undesired homogeneous reactions.

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Section: Introductionmentioning

confidence: 99%

RETRACTED: Computational Fluid Dynamics Modeling of the Catalytic Partial Oxidation of Methane in Microchannel Reactors for Synthesis Gas Production

Chen

Song

2018

Processes

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“…Conversion of methane over catalysts based on highly dispersed Ni particles from spinel NiAl 2 O 4 has also received some attention due to its structural as well as chemical stability. [45][46][47] However, if stoichiometric bulk NiAl 2 O 4 is used, it can theoretically result in a Ni loading as high as 33.3%, which would, very likely, lead to the formation of undesired large Ni particles. In addition, reduction of NiAl 2 O 4 requires higher temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…The unique textural and morphological properties of these catalysts were associated with promising catalytic activity and higher selectivity to syngas in the POM compared to many reported analogous Ni catalysts. [42][43][44][45] 2 | MATERIALS AND METHODS…”

Section: Introductionmentioning

confidence: 99%

Enhanced selectivity of syngas in partial oxidation of methane: A new route for promising Ni‐alumina catalysts derived from Ni/ γ‐AlOOH with modified Ni dispersion

et al. 2020

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Partial oxidation of methane was studied over new Ni nanocatalysts prepared from Ni-impregnated γ-AlOOH, which were compared with their counterparts derived from impregnated γ-Al 2 O 3 and α-Al 2 O 3. The prepared catalysts were characterized by powder X-ray diffraction (XRD), N 2-sorption, H 2-temperatue programmed reduction, scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis, CO 2-and NH 3-temperatureprogrammed desorption, Raman spectroscopy, CO chemisorption, and diffuse reflectance infrared Fourier transform spectroscopy of adsorbed CO. Employing γ-AlOOH as the support precursor resulted in significantly improved textural properties and catalytic activity. The structure of the support precursor and its surface properties showed a strong influence on the type of Ni active species and their interactions with the support. γ-AlOOH-derived catalysts showed NiO as the dominant Ni species when calcined at 500 C to 650 C, while NiAl 2 O 4 became the sole phase at higher temperatures. On the other hand, mixtures of NiO and NiAl 2 O 4 formed over γ-Al 2 O 3 , calcined before impregnation, regardless of the precalcination temperature. All γ-AlOOHderived catalysts showed higher specific surface areas compared to their counterparts derived from impregnated γ-Al 2 O 3. Upon calcination at moderate temperatures, γ-AlOOH-derived catalysts also showed modified textural and morphological properties of the Ni active particles, including higher Ni dispersion, larger metal surface area, and smaller Ni crystallites. The support precursor and the pretreatment conditions showed a strong influence on the catalytic performance, which was referred to their significant effect on the type of the Ni species and interactions with the support. All catalysts showed higher catalytic activity than the α-Al 2 O 3-derived catalyst, with CH 4 conversion between 86% and 88.5% at 700 C. While γ-AlOOHand γ-Al 2 O 3-derived catalysts calcined at 650 C showed a stable CH 4 conversion around 88%, and higher syngas

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“…Another significant difference among A10 samples and samples with higher load of nickel, is wide band in NIR region located between 850 and 1250 nm attributed to the ν 1 ( 3 A 2g → 3 T 2g ) transition of Ni 2+ in octahedral symmetry in nickel aluminate lattice [21,23]. Absorption maxima placed at 600 and 640 nm are common for all composite samples and originate from tetrahedrally coordinated Ni 2+ species in the nickel aluminate lattice [21][22][23]. In order to estimate band-gap energy of alumina and composites and identify energies of electron transitions, DRS spectra were transformed to Tauc's plots (Fig.…”

Section: Optical Characterizationmentioning

confidence: 99%

Application of Ni(II)-alumina composites for electrocatalytic reduction of 4-nitrophenol

et al. 2020

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Nickel-alumina composites with various content of nickel were synthetized by sol-gel method. The characterization of samples was performed by diffuse reflectance spectroscopy and electrochemical impedance spectroscopy using the Mott-Schottky analysis. Glassy carbon electrode modified by synthesized composites was investigated for reduction of 4-nitrophenol. Modification of glassy carbon electrode with composite sample led to the strong apparent electrocatalysis. Principal component analysis was used to establish correlation between structural, textural and electrochemical data of investigated composites.

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Effect of Ni/Al molar ratio on the performance of substoichiometric NiAl 2 O 4 spinel-based catalysts for partial oxidation of methane

Cited by 70 publications

References 43 publications

RETRACTED: Computational Fluid Dynamics Modeling of the Catalytic Partial Oxidation of Methane in Microchannel Reactors for Synthesis Gas Production

RETRACTED: Computational Fluid Dynamics Modeling of the Catalytic Partial Oxidation of Methane in Microchannel Reactors for Synthesis Gas Production

Enhanced selectivity of syngas in partial oxidation of methane: A new route for promising Ni‐alumina catalysts derived from Ni/ γ‐AlOOH with modified Ni dispersion

Application of Ni(II)-alumina composites for electrocatalytic reduction of 4-nitrophenol

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