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Nb-doped hematites for decomposition of isopropanol: Evidence of surface reactivity by in situ CO adsorption

Paper ID Volume ID Publish Year Pages File Format Full-Text
42492 45928 2009 5 PDF Available
Title
Nb-doped hematites for decomposition of isopropanol: Evidence of surface reactivity by in situ CO adsorption
Abstract

A series of Nb-containing hematites, Fe2−xNbxO3 (%Nb = 0.00, 1.49, 5.00 and 9.24) were prepared using a conventional co-precipitation method. Room-temperature Mössbauer spectroscopy and powder X-ray diffraction measurements suggested the formation of a crystalline phase with partial substitution of Fe3+ by Nb5+. The reactivity of these Fe2−xNbxO3 materials as catalysts was investigated using the decomposition of isopropanol as a model reaction. Theoretical calculations and CO adsorption monitored by in situ infrared absorption spectroscopy showed that the presence and the position of substituting niobium atoms in the structure of hematite modify its surface properties. The results from this study also show that the presence of Nb changes the catalytic properties toward a preferential formation of propene, presumably because of the addition of oxygen vacancies. All catalysts show high catalytic activity, and reach total isopropanol conversion above 375 °C. Moreover, the material with high Nb content reaches total conversion at lower temperatures, at approximately 290 °C with conversion to propene of 92%.

Graphical abstractIsopropanol is an ideal probe for selectivity in catalysis, because it can undergo both dehydrogenation and dehydration reactions. All catalysts show high catalytic activity, and reach total isopropanol conversion above 375 °C. The materials with high Nb content reach total conversion at lower temperatures, approximately 290 °C. This highlights the role of the niobium in the activity of the catalyst.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Hematite; Niobium; CO adsorption; Selective catalyst
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Nb-doped hematites for decomposition of isopropanol: Evidence of surface reactivity by in situ CO adsorption
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 368, Issues 1–2, 31 October 2009, Pages 17–21
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
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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
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Any Questions? feel free to contact us