Rare earth oxides doped NiO/γ-Al2O3 catalyst for oxidative dehydrogenation of cyclohexane

AbdelDayem, Hany M.; Faiz, M.; Abdel‐Samad, Hesham S.; Hassan, Salah A.

doi:10.1016/s1002-0721(14)60461-0

Cited by 26 publications

(11 citation statements)

References 33 publications

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“…[2,[18][19][20][21][22][23] We show that the observed differences in the catalysts' performance are ultimately linked to both structural and redox evolution within the evolving ensembles of thermally accessible catalyst states under applied reaction conditions. The desirable products obtained by the oxidative dehydrogenation (ODH) of cyclohexane are the partially dehydrogenated intermediates, such as cyclohexene (precursor of adipic acid), [24] cyclohexadiene (precursor for poly-additions [25] and synthetic reagent [26] ), and cyclohexanone (precursor of widely used synthetic polymer, Nylon-6, [27] and primary component of Ketone-Aldehyde Oil). [28] These occur before the formation of benzene, the possible final C6 product, and CO/CO 2 , the undesired combustion products.…”

Section: Introductionmentioning

confidence: 99%

“…The desirable products obtained by the oxidative dehydrogenation (ODH) of cyclohexane are the partially dehydrogenated intermediates, such as cyclohexene (precursor of adipic acid), cyclohexadiene (precursor for poly‐additions and synthetic reagent), and cyclohexanone (precursor of widely used synthetic polymer, Nylon‐6, and primary component of Ketone‐Aldehyde Oil) . These occur before the formation of benzene, the possible final C6 product, and CO/CO 2 , the undesired combustion products.…”

Section: Introductionmentioning

confidence: 99%

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Oxidative Dehydrogenation of Cyclohexane by Cu vs Pd Clusters: Selectivity Control by Specific Cluster Dynamics

Halder

Zhai

et al. 2020

ChemCatChem

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Supported subnanometer clusters can exhibit catalytic properties not observed in their bulk analogues. Partially‐oxidized Pd and Cu clusters are reported to catalyze the oxidative dehydrogenation of cyclohexane with high activity, and with distinctly different selectivity, producing primarily benzene or cyclohexene, respectively. Under the appliedreaction conditions, the structure and oxidation state of the two catalysts evolve differently, which leads to either the desorption of the cyclohexene intermediate or to its deeper dehydrogenation. Under the applied reaction conditions, the initially oxidized Pd and Cu clusters undergo partial reduction, which we show to be required for the selectivity to emerge. Both systems also have thermal access to multiple distinct structural forms yielding statistical ensembles. The structures within these ensembles evolve with the changing nature of the bound reaction intermediates differently for the two metals; the evolution is found pronounced in the Cu clusters, but only modest in Pd. Ultimately, the different selectivity observed experimentally for the Cu versus Pd clusters is controlled by differences in the collective structural and redox dynamics of their ensembles.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oxidative Dehydrogenation of Cyclohexane by Cu vs Pd Clusters: Selectivity Control by Specific Cluster Dynamics

Halder

Zhai

et al. 2020

ChemCatChem

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“…Finally, the peaks at 650-800 • C, present in all the catalytic systems, can be assigned to the reduction of highly dispersed non-stoichiometric amorphous nickel-aluminate spinels and bulk nickel-aluminates [38]. The Ni-Al-M1 catalyst presented a marked peak at 340 • C, evidencing the presence of some Ni 2+ species poorly interacting with alumina, similar to that of bulk or free NiO [36,39,40]. As the temperature rises, more signals appear and they are indicative of nickel species with a higher interaction with the support.…”

Section: Structured Catalysts Characterizationmentioning

confidence: 90%

“…There are peaks at low (300-400 • C), medium (400-650 • C) and high temperatures (650-800 • C). The first ones correspond to Ni species with weak interaction with alumina (bulk-like NiO) [36], whereas the ones at 400-650 • C are indicative of higher interactions with the support [37]. Finally, the peaks at 650-800 • C, present in all the catalytic systems, can be assigned to the reduction of highly dispersed non-stoichiometric amorphous nickel-aluminate spinels and bulk nickel-aluminates [38].…”

Section: Structured Catalysts Characterizationmentioning

confidence: 95%

FeCrAlloy Monoliths Coated with Ni/Al2O3 Applied to the Low-Temperature Production of Ethylene

et al. 2018

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This paper investigates the oxidative dehydrogenation of ethane to produce ethylene at low temperatures (500 • C) in metallic structured substrates. To check this point, the FeCrAlloy ® monoliths with different channel sizes (289-2360 cpsi) were prepared. The monoliths were coated with a Ni/Al 2 O 3 catalyst (by washcoating of alumina and the latter nickel impregnation) and characterized by Scanning Electron Microscopy and Energy-Dispersive X-ray analysis (SEM-EDX), Temperature-Programmed Reduction (TPR), X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). The catalytic results showed that all monoliths coated with~300 mg of catalyst presented similar ethane conversion (15%) at 450 • C. However, the lowest selectivity to ethylene was found for the monolith with the lower channel size and the higher geometric surface area, where a heterogeneous catalyst layer with Ni enriched islands was generated. Therefore, it can be said that the selectivity to ethylene is linked to the distribution of Ni species on the support (alumina). Nevertheless, in all cases the selectivity was high (above 70%). On the other hand, the stability in reaction tests of one of the coated monoliths was done. This structured catalyst proved to be more stable under reaction conditions than the powder catalyst, with an initial slight drop in the first 8 h but after that, constant activity for the 152 h left.

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“…The main signal is located at binding energy (BE) values ranging from 856.1 to 856.6 eV, higher than that of the unsupported nickel oxide (854.0 eV) [32], thus demonstrating the presence of Ni 2+ dispersed on the surface [33,34].…”

Section: Characterization Of Active Sitesmentioning

confidence: 95%

Novel Ni-Ce-Zr/Al2O3 Cellular Structure for the Oxidative Dehydrogenation of Ethane

et al. 2017

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A novel γ-alumina-supported Ni-Ce-Zr catalyst with cellular structure was developed for oxidative dehydrogenation of ethane (ODHE). First, powdered samples were synthesized to study the effect of both the total metal content and the Ce/Zr ratio on the physicochemical properties and performance of these catalysts. All synthesized powdered samples were highly active and selective for ODHE with a maximum ethylene productivity of 6.94 µmol ethylene g act cat −1 s −1 . According to the results, cerium addition increased the most reducible nickel species population, which would benefit ethane conversion, whereas zirconium incorporation would enhance ethylene selectivity through the generation of higher amounts of the least reducible nickel species. Therefore, the modification of active site properties by addition of both promoters synergistically increases the productivity of the Ni-based catalysts. The most efficient formulation, in terms of ethylene productivity per active phase amount, contained 15 wt% of the mixed oxide with Ni 0.85 Ce 0.075 Zr 0.075 composition. This formulation was selected to synthesize a Ni-Ce-Zr/Al 2 O 3 structured body by deposition of the active phase onto a homemade γ-alumina monolith. The structured support was manufactured by extrusion of boehmite-containing dough. The main properties of the Ni 0.85 Ce 0.075 Zr 0.075 powder were successfully preserved after the shaping procedure. In addition, the catalytic performance of the monolithic sample was comparable in terms of ethylene productivity to that of the powdered counterpart.

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Rare earth oxides doped NiO/γ-Al2O3 catalyst for oxidative dehydrogenation of cyclohexane

Cited by 26 publications

References 33 publications

Oxidative Dehydrogenation of Cyclohexane by Cu vs Pd Clusters: Selectivity Control by Specific Cluster Dynamics

Oxidative Dehydrogenation of Cyclohexane by Cu vs Pd Clusters: Selectivity Control by Specific Cluster Dynamics

FeCrAlloy Monoliths Coated with Ni/Al2O3 Applied to the Low-Temperature Production of Ethylene

Novel Ni-Ce-Zr/Al2O3 Cellular Structure for the Oxidative Dehydrogenation of Ethane

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