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Unraveling the contribution of structural phases in Ni–Nb–O mixed oxides in ethane oxidative dehydrogenation

Paper ID Volume ID Publish Year Pages File Format Full-Text
55171 47042 2012 8 PDF Available
Title
Unraveling the contribution of structural phases in Ni–Nb–O mixed oxides in ethane oxidative dehydrogenation
Abstract

The role of each structural phase present in highly active and selective Ni0.85Nb0.15 catalyst in ethane oxidative dehydrogenation is investigated. Based on previous studies, Ni0.85Nb0.15 consists of a Ni–Nb solid solution and a Nb-rich amorphous phase. A series of Ni-based mixed oxides with low Nb content simulating the Ni–Nb solid solution and an amorphous Nb-rich sample were synthesized and studied separately. The catalytic tests demonstrated that the introduction of even a tiny amount of Nb (atomic ratio: Nb/(Ni + Nb) = 0.01) leads to a drastic increase in ethylene selectivity (150%) compared to pure NiO. Selectivity gradually increases with increasing Nb loading up to 15%, in parallel with the decrease in oxygen desorbed as measured by O2-TPD. Based on the results of combined catalytic testing and physicochemical characterization, Ni–Nb solid solution can be identified as the key component for the high ethylene selectivity of the Ni0.85Nb0.15 catalyst, as the insertion of even a small amount of Nb drastically decreases the electrophilic oxygen species responsible for the total oxidation reactions. Co-existence of the Ni–Nb solid solution with the amorphous Nb-rich phase does not influence significantly the catalytic properties of the material.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (59 K)Download as PowerPoint slideHighlights► Investigation of low Nb content Ni–Nb–O mixed oxides simulating the Ni–Nb solid solution and of an amorphous Nb-rich sample. ► Ni–Nb solid solution was established as the key component for the high ethylene selectivity of the Ni0.85Nb0.15 catalyst. ► Co-existence of Ni–Nb solid solution with amorphous Nb-rich phase does not influence significantly the catalytic properties.

Keywords
Ethane oxidative dehydrogenation; Nickel-based mixed oxides; Solid solution; Temperature programmed oxygen desorption; CO-temperature programmed reduction
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Unraveling the contribution of structural phases in Ni–Nb–O mixed oxides in ethane oxidative dehydrogenation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 192, Issue 1, 30 September 2012, Pages 169–176
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us