Investigation of Ce–Zr Oxide‐Supported Ni Catalysts in the Steam Reforming of <i>meta</i>‐Cresol as a Model Component for Bio‐Derived Tar

Hoang, Thi Minh Chau; Rao, N. Koteswara; Lefferts, Leon; Seshan, Kulathuiyer

doi:10.1002/cctc.201402857

Cited by 22 publications

(16 citation statements)

References 50 publications

(72 reference statements)

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“…[20,44] In particular, zirconia has been extensively studied as a support and a catalyst in reforming processes, [13,12,14,10,9] where the water-gas shift cycle and the formate formation from CO and water are the key steps. Nonetheless, understanding of the performance of zirconia in the process remains incomplete.…”

Section: Introductionmentioning

confidence: 99%

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Bazhenov

Honkala

2016

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Under the water-rich pre-treatment and/or reaction conditions, structure and chemistry of the monoclinic zirconia surfaces are strongly influenced by oxygen vacancies and incorporated water. Here, we report a combined first-principles and atomistic thermodynamics study on the structure and stability of selected surfaces of the monoclinic zirconia. Our results indicate that among the studied surfaces, the most stable (111) surface is the least vulnerable towards oxygen vacancies in contrast to the less stable (011) and (101) surfaces, where formation of oxygen vacancies is energetically more favorable. Furthermore, we present a vigorous, systematic screening of water incorporation onto the studied surfaces. We observe that the greatest stabilization of the surfaces is achieved when a part of the adsorbed water molecules is dissociated. Nevertheless, the importance of water dissociation for achieving the greatest stabilization is high for the less stable (011) and (101) surfaces, while completely hydrated (111) surface is stabilized equally regardless of the water dissociation state. Analysis of the constructed phase diagrams reveals that the (111) surface remains preferably clean and the (011) and (101) surfaces have dissociated water at low coverage under the reactive conditions of T = 600-900 K and p(H 2 O) < 1 bar. Upon temperature decrease and/or pressure increase, all studied surfaces gradually uptake water until fully hydrated. All in all, our findings complement and broaden the existing picture of the structure and stability of the monoclinic zirconia surfaces under the pre-treatment and/or reaction conditions, enabling rationalization of the potential roles of zirconia as a heterogeneous support and a catalyst component.

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Section: Introductionmentioning

confidence: 99%

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Bazhenov

Honkala

2016

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“…This point confirms that crystalline zirconium oxide is not present, not even in the sample with a higher amount of Zr, in agreement with XRD results. Differently, at increasing Ce content in the samples, the characteristic band at 462 cm −1 of cerium oxide with fluorite-type structure appears with higher intensity in the spectra, along with two additional bands at 225 and 635 cm −1 , directly related to the CeO2 lattice defects caused by oxygen vacancies and the modification of the oxygen sub-lattice [13,25,[26][27][28][29][30][31].…”

Section: Characterization Of Active Sitesmentioning

confidence: 82%

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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“…For the sample of pure ceria, the Raman spectrum shows a sharply peak located at 465 cm −1 . This peak is ascribed to the F 2g vibrational mode of the fluorite‐type structure of cerianite . The peak at 550 cm −1 is attributed to the oxygen vacancy (O v ) that derives from Ce 3+ ‐V O complexes.…”

Section: Resultsmentioning

confidence: 99%

“…In order to suppress carbon deposition and prevent Ni sintering, many works have been done to design and develop new catalysts . As a multifunctional material, CeO 2 can be not only used as promoter but also as support of nickel due to its gasification of deposited coke . Moreover, metal‐doped ceria has received great attention .…”

Section: Introductionmentioning

confidence: 99%

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Optimizing the preparation of Ni‐Ce‐Pr catalysts for efficient hydrogen production by n ‐dodecane steam reforming

et al. 2019

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Summary Nowadays, the development of fuel cell is getting more and more inseparable from the production of hydrogen. Long‐chain hydrocarbons steam reforming is a feasible way for hydrogen supply. Herein, various nickel‐ceria‐praseodymium (Ni‐Ce‐Pr) catalysts have been prepared by a sol‐gel method. Multiple parameters during catalyst preparation, including the amount of Ni, the content of doped Pr and the calcination temperature, were systematically studied for tuning the catalytic performance for n‐dodecane steam reforming in a fixed‐bed reactor under 15 mL/gcat·h at 600°C and water‐to‐carbon molar ratio of 2 at 0.1 MPa. Reaction data showed that both the amount of Ni and the content of doped Pr will greatly affect the n‐dodecane conversion and hydrogen production. Additionally, the calcination temperature during catalyst preparation showed a big influence on its performance for n‐dodecane steam reforming. After optimization, 10Ni‐CePr2‐600 exhibits the highest activity and stability for n‐dodecane steam reforming, accompanying with the lowest rate of coke deposition (0.015 gc/gcat·h). The structure and oxygen vacancy of the catalyst was characterized by H2‐TPR, Raman, and X‐ray photoelectron spectroscopy (XPS). The superior activity and stability of 10Ni‐CePr2‐600 are ascribed to the strong interaction between NiO and support along with abundant oxygen vacancies in the Pr‐doped ceria.

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Investigation of Ce–Zr Oxide‐Supported Ni Catalysts in the Steam Reforming of meta‐Cresol as a Model Component for Bio‐Derived Tar

Cited by 22 publications

References 50 publications

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

Understanding Structure and Stability of Monoclinic Zirconia Surfaces from First-Principles Calculations

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

Optimizing the preparation of Ni‐Ce‐Pr catalysts for efficient hydrogen production by n ‐dodecane steam reforming

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