Nb effect in the nickel oxide-catalyzed low-temperature oxidative dehydrogenation of ethane

Handle URI:
http://hdl.handle.net/10754/562045
Title:
Nb effect in the nickel oxide-catalyzed low-temperature oxidative dehydrogenation of ethane
Authors:
Zhu, Haibo; Ould-Chikh, Samy ( 0000-0002-3486-0944 ) ; Anjum, Dalaver Hussain; Sun, Miao; Biausque, Gregory; Basset, Jean-Marie ( 0000-0003-3166-8882 ) ; Caps, Valerie
Abstract:
A method for the preparation of NiO and Nb-NiO nanocomposites is developed, based on the slow oxidation of a nickel-rich Nb-Ni gel obtained in citric acid. The resulting materials have higher surface areas than those obtained by the classical evaporation method from nickel nitrate and ammonium niobium oxalate. These consist in NiO nanocrystallites (7-13 nm) associated, at Nb contents >3 at.%., with an amorphous thin layer (1-2 nm) of a niobium-rich mixed oxide with a structure similar to that of NiNb 2O 6. Unlike bulk nickel oxides, the activity of these nanooxides for low-temperature ethane oxidative dehydrogenation (ODH) has been related to their redox properties. In addition to limiting the size of NiO crystallites, the presence of the Nb-rich phase also inhibits NiO reducibility. At Nb content >5 at.%, Nb-NiO composites are thus less active for ethane ODH but more selective, indicating that the Nb-rich phase probably covers part of the unselective, non-stoichiometric, active oxygen species of NiO. This geometric effect is supported by high-resolution transmission electron microscopy observations. The close interaction between NiO and the thin Nb-rich mixed oxide layer, combined with possible restructuration of the nanocomposite under ODH conditions, leads to significant catalyst deactivation at high Nb loadings. Hence, the most efficient ODH catalysts obtained by this method are those containing 3-4 at.% Nb, which combine high activity, selectivity, and stability. The impact of the preparation method on the structural and catalytic properties of Nb-NiO nanocomposites suggests that further improvement in NiO-catalyzed ethane ODH can be expected upon optimization of the catalyst. © 2011 Elsevier Inc. All rights reserved.
KAUST Department:
KAUST Catalysis Center (KCC); Physical Sciences and Engineering (PSE) Division; Chemical Science Program
Publisher:
Elsevier BV
Journal:
Journal of Catalysis
Issue Date:
Jan-2012
DOI:
10.1016/j.jcat.2011.10.005
Type:
Article
ISSN:
00219517
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorZhu, Haiboen
dc.contributor.authorOuld-Chikh, Samyen
dc.contributor.authorAnjum, Dalaver Hussainen
dc.contributor.authorSun, Miaoen
dc.contributor.authorBiausque, Gregoryen
dc.contributor.authorBasset, Jean-Marieen
dc.contributor.authorCaps, Valerieen
dc.date.accessioned2015-08-03T09:43:30Zen
dc.date.available2015-08-03T09:43:30Zen
dc.date.issued2012-01en
dc.identifier.issn00219517en
dc.identifier.doi10.1016/j.jcat.2011.10.005en
dc.identifier.urihttp://hdl.handle.net/10754/562045en
dc.description.abstractA method for the preparation of NiO and Nb-NiO nanocomposites is developed, based on the slow oxidation of a nickel-rich Nb-Ni gel obtained in citric acid. The resulting materials have higher surface areas than those obtained by the classical evaporation method from nickel nitrate and ammonium niobium oxalate. These consist in NiO nanocrystallites (7-13 nm) associated, at Nb contents >3 at.%., with an amorphous thin layer (1-2 nm) of a niobium-rich mixed oxide with a structure similar to that of NiNb 2O 6. Unlike bulk nickel oxides, the activity of these nanooxides for low-temperature ethane oxidative dehydrogenation (ODH) has been related to their redox properties. In addition to limiting the size of NiO crystallites, the presence of the Nb-rich phase also inhibits NiO reducibility. At Nb content >5 at.%, Nb-NiO composites are thus less active for ethane ODH but more selective, indicating that the Nb-rich phase probably covers part of the unselective, non-stoichiometric, active oxygen species of NiO. This geometric effect is supported by high-resolution transmission electron microscopy observations. The close interaction between NiO and the thin Nb-rich mixed oxide layer, combined with possible restructuration of the nanocomposite under ODH conditions, leads to significant catalyst deactivation at high Nb loadings. Hence, the most efficient ODH catalysts obtained by this method are those containing 3-4 at.% Nb, which combine high activity, selectivity, and stability. The impact of the preparation method on the structural and catalytic properties of Nb-NiO nanocomposites suggests that further improvement in NiO-catalyzed ethane ODH can be expected upon optimization of the catalyst. © 2011 Elsevier Inc. All rights reserved.en
dc.publisherElsevier BVen
dc.subjectEthaneen
dc.subjectNanocompositesen
dc.subjectNickelen
dc.subjectNiobiumen
dc.subjectOxidative dehydrogenationen
dc.titleNb effect in the nickel oxide-catalyzed low-temperature oxidative dehydrogenation of ethaneen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentChemical Science Programen
dc.identifier.journalJournal of Catalysisen
dc.contributor.institutionFEI Company, 5350 NE Dawson Creek Drive, Hillsboro, OR 97124, United Statesen
kaust.authorZhu, Haiboen
kaust.authorOuld-Chikh, Samyen
kaust.authorSun, Miaoen
kaust.authorBiausque, Gregoryen
kaust.authorBasset, Jean-Marieen
kaust.authorCaps, Valerieen
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