fulltext.study @t Gmail

Influence of the cobalt salt precursors on the cobalt speciation and catalytic properties of H-ZSM-5 modified with cobalt by solid-state ion exchange reaction

Paper ID Volume ID Publish Year Pages File Format Full-Text
42413 45924 2009 9 PDF Available
Title
Influence of the cobalt salt precursors on the cobalt speciation and catalytic properties of H-ZSM-5 modified with cobalt by solid-state ion exchange reaction
Abstract

Co-ZSM-5 catalysts prepared by either aqueous or solid-state ion exchange using different cobalt precursors (acetate, chloride, nitrate or formate) were studied in the selective ammoxidation of ethylene and ethane to acetonitrile. Co2+ supported catalysts were characterized by chemical analysis, X-ray powder diffraction, N2 adsorption (BET), TEM/EDX, FTIR, XANES and EXAFS spectroscopy, H2 TPR and TPD of ammonia. It was found that all the preparations led to cobalt exchanged metal ion at the bridging oxygen of Si–OH–Al groups or to Co oxide or phyllosilicate. XRD, TEM and H2 TPR indicated the presence of cobalt oxide when cobalt chloride, formate or nitrate was used. TPD of ammonia and FTIR of pyridine, used respectively as probe molecules showed that solid-state exchange catalysts exhibited new Lewis acid sites. The catalyst resulting from cobalt acetate, which contained mostly isolated Co2+ ions in cationic exchange position and cobalt phyllosilicate, showed high activity and selectivity toward acetonitrile.

Graphical abstractAmmoxidation of light hydrocarbons was tested over Co-ZSM-5 catalysts. The cobalt salt precursors had an important influence on the physico–chemical and catalytic properties. The preparation procedure results in the disappearance of Brönsted acid sites and the creation of new Lewis acid sites. Furthermore, TEM/EDX, H2-TPR and XRD indicated the presence of cobalt oxide when cobalt chloride, formate or nitrate was used. In fact, a cobalt phyllosilicate phase is present at the outer surface of the zeolite for the sample issued from cobalt acetate as precursor.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Co-ZSM-5; Solid-state reactions; Precursor; Speciation; Ammoxidation; Spectroscopy; XANES/EXAFS; TEM/EDX
First Page Preview
Influence of the cobalt salt precursors on the cobalt speciation and catalytic properties of H-ZSM-5 modified with cobalt by solid-state ion exchange reaction
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
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 357, Issue 1, 31 March 2009, Pages 42–50
Authors
, , ,
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